Question 1: "George what is the best scale twin to start with?"
Twinman: "Unfortunately there are very few scale twins to start with available at this point. Most warbirds have the worst possible aspects of twin learning flight. Small rudders, short tail moment, and high wing loading are very bad places to start you twin career.
If we confine the discussion to scale planes, I would have to say the DC-3 and for the ARF crowd, the VQ A-26 reviewed in this site. Both are reasonably docile airplanes and reasonable single engine out flight characteristics. Whatever you decide, please review my suggestions before flying any twin. It is not the same as a single engine plane."
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Question 2: " I am building a 1/8 scale DH Mosquito from a set of Brian Taylor plans, the plane is about 45% done and I am in the process of mounting the engines. I will be using the Saito 72, the plan calls for the starboard engine to run in the reverse direction. How can I do this? and if I cannot get the engine running in the reverse direction, would this affect the plane in any way ? One last question, in single engine aircraft, the engine is at a certain offset, of some degree, I was told that twins do not need any offset at all, is this true?
Twinman: "Sir, Most four strokes require a reverse rotation camshaft, so can only suggest to contact Saito. As for the offset, I have heard many ideas on this, but can only say I run mine straight ahead or maybe down as the vertical climb test indicates. One line of thought is that off setting the engines out will assist if engine out. Better to make sure of reliability before worrying about offset. The benefit of reverse rotation is not so important on small models and only adds to the complexity of the model and starting problems. Good Luck, Twinman"
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Question 3: "Mr. Twinman, in an answer to a recent question (B. Taylor Mosquito), you mention that on smaller models, counter-rotation doesnt really help you. At what point should one consider counter-rotation? Im building a Bates Plans Martin B-26 Marauder with 110 wingspan. Im waiting to determine weight before deciding on engine size. Most likely will be two O S 120 Surpasses, or worst case, two Saito 180s. No offset for these engines straight ahead
Twinman: "Sir, If you go back to page two of the twin engine forums, there was a lot of discussion on reverse rotation engines. The P-38 used it to reduce the buffeting on the center fuse section. Originally it had inward rotating engines and changed to outward. Yes, I have counter rotating engines on my silver P-38 as it is easy to do on ST engines and is the correct configuration for the P-38. Does it fly any different than the other 100 plus inch twins I have?...not really, that can be attributed to counter rotation. My converted Ultra Sport 1000 does not use it and it is fully aerobatic. I will be the first to admit that I am not an aeronautical engineer so the exact benefit I cannot attest to or argue about on Model airplanes. I have not seen the difference to warrant the increased cost and aggravation. You know that it will take new cams for those four stroke engines to reverse them don't you? Good Luck, Twinman"
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Question 4: "Twinman, I posted this question under twins in Forum 1 but may have done it incorrectly. I'm new to this web page (and I love it!!). I loved your review of VQ Models A-26 Invader ARF because it answered so many questions I have about the one I am building. It's the same kit and also black. I was hoping that you might fill in a few blanks for me. Which Spring Air retracts did you use (main and nose)? I have no experience with air retracts, only cheap mechanical. Gyros - I like the idea but again no experience. I understand the rudder gyro (sort of) but you said you used a gyro for the ailerons and adjusted the gain control (I assume a knob?) on the transmitter to adjust. I'm using a JR XP652 6 ch. Radio and I think your review mentioned the use of a Futaba T6XA which is similar. Neither have a gain control as far as I know. How can I set a gyro for the ailerons using my radio? One last question. I would like to put a pilot in my plane but can't seem to find WWII scale (or semi scale) bomber/flying pilot figures. Do you know of any? I think they should be 1/12th size? Thanks in advance for the help and guidance. I love this place!!!! p.s. I have building pics if interested. I also mounted OS 52 4 strokes 90 degrees and used Hitech micro servos for the throttle. Perfect alignment although the head will stick out the side rather than the bottom like yours"
Twinman: "Sir, Sorry for delay to answer, Job that supports hobby gets in the way of quality hobby time. Will check with the modeler who I built the A-26 for the retracts. Mind is going with hair and that was one year ago, or check with Spring Air them selves at http://www.retracts.com/. The early posts in this forum cover the use of Gyros including the aileron gyro. I used the Hobbico Aero for the ailerons as it has dual input and output. You need a rotary knob for the gain control or if you can set the high and low limits on the fifth or sixth channel you can do the same thing. The Hobbico multi purpose can also be used if you only use on channel for the ailerons. It does not require an auxiliary channel for sensitivity control. As for pilots,I would open that to discussion or go see the local hobby store. Good Luck, Twinman." Added: "Discussed the retracts on the A-26 with Spring Air ( A nice bunch of people) and Morris ( Also very accommodating). The retracts that the modeler supplied me with and I installed were Spring Air 105. These are not the best installation due to the fact that the nose gear mount must be modified. Per Spring Air there are two sets you can use. The 102 set will bolt in, but in my opinion, is not the best as it uses two cables for steering. The set I installed used this and you will have problems with the cables in the retracted position. The better set, per Spring Air, is the 202 set that uses a push pull rod for steering. George" Update: I spoke to Bob at Morris Hobbies and he has confirmed the retract set they are going to use in the new shipment of the A26 is our 101 gear. This is a firewall mount nose unit.. Bob informed me the new fuselage have a firewall installed.
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Question 5: "hey, I am starting a 51" wingspan b-25 electric kit. I plan to use some speed 700 series motors, jeti 60 speed control and 20 2400scr cells. It has a fiberglass fuselage and balsa ribbed wings. I need any and all input."
Twinman: "Hi Michael, I will readily admit that I have little knowledge of electric's. I have heard that wiring the motors in series is really the best idea, in that it completely eliminates one engine dying before the other. If you will go to the forth page of the twins forum, I posted the following for what is supposed to be one of the best electric sources of information. Good luck, Twinman
"I admit that electric is not my thing, but that is only because I have not tried it...Yet. Running out of new challenges...Until next P-38 ( Another story) As there seemed to be interest in electric warbirds and this is a warbird site, I found the enclosed electric warbird site. Let's see who has others. Try a company called Electric Areo Modeling USA at http://www.eam.net/ Skip the home page, the multi's are at http://www.eam.net/EAMRC/scalemulti.htm Any place with three P-38 kits is ok by me!!!!!"
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Question 6: "Need a good setup for first flight for my p38 Yellow has two BME 44 no fuel 33.2 lbs two 24 OZ tanks. First large twin Thanks Phil"
Twinman: "Phil, Could you please let me know what you mean by good "set up"? I would not recommend the P-38 for a first twin. It has very heavy wing loading and lands faster than most trainers can fly, at that weight. By all means, use the flaps for take off and landing, Would suggest 50% for take off and full for landing. Reliability is the key to this plane. Do not assume that single engine operation is possible and plan your preparation for engine out. Always use a helper for any twin. I would strongly suggest that you use two people to hold the plane and another to control the radio. Go to full power and, with two people, hold the plane straight up for 10 seconds. Listen to the engines. Any sag......ANY change, fix it!!!!!! NOW!!! Note the posts in the twins forum under "P-38" and the two in-flight failures of engines. I am not trying to scare you, only to stress that reliability is very important. I would consider gyros on the rudders and ailerons, for additional safety. I have posted in the early twins forums about their use. This stabilizes the plane additionally. At take off, plane on inputting elevator. The real plane and the model are similar in that they do not fly off the ground on their own. Good Luck, Send pictures. Twinman "
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Question 7: "Mr. Twinman, I have scratch built a Cessna Skymaster at 1/6 scale. It flies with 2 St GS.40's with power to spare. The props I use are Master airscrew 10x6 both the puller and pusher. When I ready for flight on the ground I rev up both engines and tune them (keeping the rear one the richest possible). But in flight when the props unload the rpms of one of the engines (or both)change at full power, should I change the pitch of the rear prop since is working and pushing in the same direction of the airstream? I enlarged the rear engine airscoop a little out of scale dimensions to improve the airflow and the engine head feels "cool" after a flight, I know is not overheating, but still cannot get in flight the same full power tuning I get in the ground. I would appreciate any suggestions you might have regarding this setup."
Twinman: "Hi Stefano, The engines will unload in flight and speed up. I think your idea of an enlarged scoop for the rear engine was well planned. Pusher props do not seem to cool as well as the tractor style. At the current state of my poor understanding, I would leave it alone. This plane with inline engines really is completely unaffected by small rpm differences. Good Luck, Twinman"
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Question 8: "Hi Twinman: I picked up a p-38 kit by Aerotech International imported from the U.K. by D.A.R.E. importers a few years ago and would like to get it started this spring. Do you know of anyone who has had experience with this kit ? Its spec's are : 74" span 50.5 length aprox.weight 8-81/2 lb I am planning to power it with with Enya 46 4cy's, onboard glow, spring air retracts and flaps. I build light, and hope to keep the wing loading down, I plan to cover it with Monokote. I have experience with scale, combat and Ducted fan types and fly with rudder. Any information you can impart would be great. Thanks in advance: Mike Daly"
Twinman: "Hi Mike, Go to the pictures of Twinman with my P-38's......the small silver one is the Aerotech that you have. I built it two years ago.....If you note the second picture.....It is no longer with us.....don't do combat!!!!Lost an engine in a dive toward the
ground going after a Mustang!! Now having said that..You will find the instructions......uh....leave a lot to the individual modeler's imagination. I built it without the removable wings. If you follow the instructions (Such that they are), the kit can be disassembled including the tail area. Don't do that!!! Adding the steel rods into the tail really made it tail heavy. Most P-38's end up tail heavy anyway, but this was bad. I also added four flaps to aid in landing. If you elect not to add flaps, consider mixing the ailerons to the elevator for increased lift. Used the preformed wire for elevator control and one servo in each boom for each of the pair of flaps. If you are going to retracts, it really gets tight in the booms. I used high torque metal gear micro servos to save weight and space. Engine out will result in a snap roll.....quick!! I used two gyros for safety and it did work....Just not straight down!! I would really worry that .46's four strokes are not enough power!!!!! Mine had two ST 60's and still took several hundred feet to get off. I also had two K&B .45's on the Wing Mfg P-38 and was really not happy with the power. OK, so I tend to build heavy. Monocoat will save a lot of weight. Watch out for a stress riser on the inside corner of the aileron cut out. The ailerons hinge at the top and as you cut out the aileron surfaces, they must be beveled to allow movement.....not in the instructions!!! If I remember correctly, I was concerned about the wing structure, so I added an arrow shaft into the wings to reinforce the structure. I also glassed the plane, which added weight, for painting. The plane can be built lighter, but watch out for tail heavy problems. I used Grappner square fuel tanks to get into the nacelles at 14 oz, but 12 would have also worked. The plastic covers need to be cut and matched to the model carefully. Small
heating helps......I said small!!!!! The final gluing of the model, wings and tail surfaces is easier with two or three of the various tools to measure incidence, used at the same time, is almost a necessity to get all the parts straight. Take your time....This is the most important part. The final part is to read and understand the instructions....as well as you can. Good Luck Twinman"
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Question 9: "Seeing as how you are the moderator I will ask you. What do you think my first twin engine plane should be? Currently fly P-51 Mustang, prop jets (training for turbines) and 1/4 scale Sukhoi. I really like the looks of the P-38. I would prefer an arf like the World Models P-38. What's your opinion. Thanks"
Twinman: "Hi, David, I think we are talking about the world models F-82. I could not find a world model P-38. I have not flown that plane, but have kit bashed several singles into a 100' standoff F-82 and I really like them. Advantage of the twin fuse designs, in my opinion. Two rudders that are at a relatively long moment from the engines. This make for better single engine control. The engines are close together, again, better control. As you can see, I want to push for the first twins, something that will not get you into trouble with a hard to control inverted snap roll with engine out. I really do not recommend the P-38 as a first twin. Rubbers too small,
engines too far apart, and very high wing loading. The Morris A-26 is a little more to handle than the F-82, but reasonable engine out control and wing loading. Set the rudder throw for max on any twin, for safety. Good Luck, Twinman"
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Question 10: " I am looking for a p-38 kit with a wing span 100inch or bigger I don't want a foam or a glass plane I want a wood built up wing and fuse I don't know much about building from plans so I don't know how hard it is to do could u let me know I have a lot of time so if it is not that hard I might build nick zirolie's p-38 thanks, nick
ps I have some pic of a p-38 called glacier girl that was restored I had the opportunity to sleep under the nose of this plane if u want I can send the pic to you. If you have not heard of this very nice plane go to http://www.thelostsquadron.com/"
Twinman: "Hi Nick, The only non foam wing kit that I know of is the Ziroli and it is 114" wing span. I really would not say that it is "Not too hard". That is a big plane and takes alot of time, space, money, and dedication. This is not a beginners kit. There are various kit cutters who will supply the kit already cut out for approx $500.00.....but that is only the beginning. If you will look at the various posts on the twins forum, there are several kits for the P-38, including one of our sponsors wing manufacturing. G&P sales has a video to review of the building of their 78" kit, as I said Wing Manufacturing is a builders 74" kit and flies well. G&L hobbies, as shown on the twins forum posts, has a 100" kit. VQ and Morris Hobbies will soon introduce an 83"arf with a built up wing that you could customize to your heart's content. Areotech from the UK also has a quick build 78"kit with foam wing, but no US distributor.
Yellow Aircraft has a 100" kit, as does Robart Manufacturing at 114". Hope this helps. If you are still looking at the Ziroli, there is a post in the twins forum for a man who is posting a website on the actual construction of that kit. Good Luck and send pictures,
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Question 11: "Dear Twinman, I just purchased the Wing Mfg. P-38, I would like to build it semiscale, retracts, bomb drop etc. I read you thought your .45 were to small, what about the Enya .53 4c, set up as counter rotating? Also what 3 blade props would you use?, thanks for enjoying my favorite war bird also, John"
Twinman: "John, Welcome to the P-38 excentic members club. Like any model, if you build it light enough it will fly better.
My Aerotech had ST 60's and 12x6 props. You will find that the P-38 usually build tail heavy, so I decided to add the weight in engines. If you will go to the old or back issues of RC Report Magazine or contact them for a reprint, they did a review of this kit in detail. The red one or "Yippie" shown on my pictures of twins was a wing manufacturing kit. As a general rule find the best prop for your engine and go down on inch in diameter. I have seen that, due to the loss of efficiency of the three blade prop, that sometimes there is little loss of rpm keeping the same diameter. This is based upon Master Airscrew props. Are you sure that you can get a reverse rotation camshaft for your engines? Make sure that you can handle the starting duties of two reverse rotating engines. You will also find that there are few pusher three blade props available, You might go to Zinger Propellers and check the situation before committing to a reverse rotation three blade system. Do not use one servo for the elevator!!!! It will flutter. I also used the micro metal gear servos to save space. If I remember correctly, the kit called for only one engine throttle servo. Bad idea. The linkage will flex, resulting in uneven engine control and real problems in setting the engines up. If you are considering inverted engines, please consider on board ignition for reliability. You did not mention about retracts. If you are not going that way, consider spring gear for the mains to reduce shock at landing to the structure. Ignore the recommendations for rudder throw......use the most you can get for a P-38. The last point is my same old warning on any twin, is reliability!!!!!! Do everything you can to avoid a engine flame out and the inverted flat spin that often comes next. This is not a good plane for your first twin. Try to get some experience with easier to fly twins first. Good Luck, And send pictures. Twinman"
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Question 12: " am building a Rich Uravitch O.V.-10 Weight 13 to 16 lb. Span 81" , wing area 1,215 sq.in., wing loading 24 to 28 oz/sq.ft. engine range .46 to .60 2 stroke .70 4 stroke. He used two o.s. .46 fx 2 strokes in the prototype and he said they did fine I e-mailed him about using two o.s. .61 fx 2 strokes, but I has not able to get to say which would be the best to use , I'm thinking of the 2 .61 fx what do you think?????????????????"
Twinman: "Hi Gary, I have a similar size Bronco as shown of the twinman page. It was scratch built and as such a bit heavy. It flew with the original owner with two ST 90's, but he felt was under powered. I have seen that the prototype did fly with two, as you said FX.46's. It must have been very light. If you can hold the wing loading to the levels you describe, the 60's would still be better in my opinion. The larger engines would also allow going to three blade props, if you so desire. I would still be concerned about aerodynamic drag due to the thick wings. Fly is one thing, enjoy it is another. My vote is for the .60's or more and throttle back as necessary.....particullarly if flying off of grass. Good luck, Twinman"
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Question 13: "Hello Twinman I'm currently building my first twin a Messerschmitt Bf 110 from a Brian Taylor plan 73" wing span, do you have any experience with this model, I think Aero Tech copied this plan and made it as a kit. It does not show flaps on the plan, do you think it's worth putting them in. I intend to install two LEO 37's inverted and sprung air retracts, I'm trying to keep the all up weight to maximum of 9.5lbs. Also you mention in your techniques article when using a Gyro on the rudder, "The rudder must move in the direction of the yaw on the ground". Does this meet that if the plane is yawing to the right the gyro puts in right rudder? Thanks for your help in advance. John Hill. "
Twinman: "Hi John, I have built the Aerotech P-38. If you can keep the flying weight at 9 pounds, I would not worry about flaps. If it goes over 12 pounds, I would consider it for landing speeds and reduced stress on the landing gear. I went to the aerotech site at http://www.atimanufacturing.co.uk/ and looked at the Aerotech model. OK, so I admit that I was not quite sure what the plane was.
Looking at it, it seems that it could suffer the same problems as the P-38 in that it has small rudders and wide engine spacing. That is a problem for engine out situations. Yes, the gyro would be a welcome addition to this plane, particularly with small rudders and a tail dragger to boot. The gyro must be set up to move the rudder the direction of the yaw to bring back the fuse to the centerline of flight. DO NOT GET THIS BACKWARDS! The rcwarbirds forums are not being displayed at this time until the decision to use them or not at rcuniverse. If you would like a personalize copy of the original set up procedures on gyros, Please let rcwarbirds.com know your e-mail and I will send directly to you. Good Luck, Twinman"
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Question 14: "Hi there, I have ordered a VQ P38. I am looking at installing 2 x Rossi 110R65 engines. These engines are rear exhaust with pumps and put out a stated 3.8 Hp at 11200rpm. Does this kit have adequate space to install the rear exhaust header and pipes. Will the headers have to be channeled to the inside or outside of the booms or are they able to be kept inside. How is the kit designed for exhaust outlets. Do you think what I am proposing is possible or should I get the side exhaust 60 size engines. I really want the rear exhaust as it boasts nearly twice the output for little less cost. But only if the exhaust can be routed correctly. Also anyone with experience with this 110R65 Rossi. As I need to know prop sizes. Thanks"
Twinman: "Hi Chis, It just so happens that rcwarbirds has "Forced me" to get involved with this project. ( What I must go through). I just finished breaking in the engines for the prototype, and they are the MVVS engines that can rotate the cylinder head to rear exhaust and that is how the prototype will fly. I did modify the rear mounted muffler to point down with two outlets per engine. The engines will be mounted inverted with on board glow drivers for secure operation. Morris Hobbies and the modeler who is building it, is looking at a special exhaust to let the exhaust out the original outlet behind the turbo supercharger. Problems.
1. If you can get the exhaust to go from down to up, you can run a oval shaped pipe above the wing and below the fiberglass cover over the wing. This is the only way that the exhaust can run if you plane to use retracts.
2. There is not room in the boom with retracts to bring the exhaust through the gear bay with the servos......There are three servos in each boom for engine, rudder, and elevator, not to mention the fuel tanks. Now with the pumped engines, it might be possible to put a large single tank in the center pod under the pilot and feed the engines from there. Note, I DO NOT RECOMMEND ANYONE THINK ABOUT THIS WITHOUT A PUMPED ENGINE!!!!!!! Absolute engine reliability is the single most important thing with a P-38. If the fuel tank could be relocated, there would be more room in the booms.
3. If you invert the engines, tuned pipes will interfere with the landing gear in the booms. If you mount upright, the pipes will ruin the scale look of the plane. I would forget about the pipes for such large engines. You do not need it.
4. That is a very large amount of power for this plane. I would strongly suggest using three blade props, maybe Master Airscrew at 14x7 pitch. Structural concerns come to mind, at that power, quickly.
5. As for other props recommendations, it just so happens that Morris Hobbies is the sole importer and support for the Rossi Engines. I would suggest contacting them directly.
6. Side exhaust will hurt the look of the plane, so rear exhaust, routed straight down would be my recommendation. Chech with Morris what he has in this department.
7. Inverted engines, if not using onboard glow, will require remote glow plug power for safety. Do not reach under an engine that is running on any plane, and particularly a twin. Good Luck, Twinman"
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Question 15: "I have just about finished building a PBY 5A with a wing span of 9ft. and weighs about 25lbs. I have powered it with two 91 Saito fa91s engines and was wondering if this is enough power for it. Fred Ness"
Twinman: "Hi Fred, I would definitely prop this for more thrust, meaning large diameter propellor and lower pitch. You will need all the thrust you can get. Yes, many of these planes are flying with that power set up, but it is definitely not over powered. Please send us pictures. Does the model have a water rudder? If not, consider to mix the engines to the rudder for more control. Good Luck, Twinman"
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Question 16: "Hi, Im building a twin boom airplane from scratch and I would like to know how to construct the linkage for the elevator and rudder and if possible as little as possible of the linkage goes on the outside of the plane"
Twinman: "For the elevator, there are commercially available elevator linkage that have a control horn soldered to the two "L" shaped brackets. Have the push rod come out of the center of the fuse's to the control horn at the rear of each fuselage. Use one servo for each end of the elevator. As for rudders, it depends upon how large the plane is and how large the rudders are. If you look at my pictures of "Twinman's Obsession". One is of a twin ugly stick. High power and speed. I use one servo for each rudder, in pull pull arrangement, in each fuselage and Y together. If you look at the "Twin John", it is smaller and smaller rudders. It has external linkage connecting the rudders at the control horns and only one servo......at six volts. As far a hiding the linkage, that will depend upon the design of the rear of the fuselage. If you want to hide as much as possible on the rudders, go to pull pull and put below the horizontal stabilizer. If I had a better idea of the size or design, maybe I could help more. These twin fuselage planes are a blast to fly and flew both of mine this weekend. Good Luck,"
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Question 17: "I recently was given an old semi built P-38 Lightning with a wingspan of 69-1/2". It seems to have most of the part minus the canopy. Are you able to identify the maker of this kit, and more importantly, recommend someone who may have a canopy that would fit this kit? Thank you, Paul O'Sullivan"
Twinman: "Hi Paul, There are several kits of the P-38 in that size or approximately that size. One is handled by Hobby Barn at http://www.hobbybarn.com/airplanes_marutaka_kits.htm These are the old Royal Manufacturing kits from Japan. The other older manufacturer is here in the US called Wing Manufacturing and they can be reached via a link at rcwarbirds.com. I would think either canopy will fit your model. The above are the older manufacturers assuming that it is a built up kit. Good Luck and send pictures. Twinman"
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Question 18: "George I am on the list for the VQ P-38. I would like to power it with either the O.S. LA 65 or the Super Tigre ST75 . What do you think? Please advise, keithw "
Twinman: "Hi Keith, If you plan to put two blade props on the plane, I would go with the LA 65's. If you plan on scale three blades such as 11x8 or even 12x6 from Master airscrew, I would look at the Super Tigre. Whatever you do, plan for maximum reliability. If you plan to invert the engines, I would strongly suggest on board glow drivers. Good Luck, Twinman"
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Question 19: "Hi George, May I humbly suggest the Dehaviland Caribou as a good candidate for a first twin? Huge rudder,elevator, long tail moment and good wing loading. Massive Aileron/flap area. Unfortunately probably only available scratch built. Attached is a photo of mine, scratch built from a set of three views. It has fantastic engine out properties, flies very well and has wonderful potential to increase its scale functions. It is not a very big model at two metres and is only powered (easily) by a pair of .25s, but I have been impressed with its ability and its robustness. They are not the most attractive looking plane around, but have a certain butt ugly appeal. Regards, Tim Bailye Kalgoorlie"
Twinman: "Hi Tim, At the risk of dating myself, I remember when the U.S. military flew the Caribou. It does fill my primary recommendations of a long tail moment, low wing loading, and large tail feathers. You even fulfill my warnings about not over powering it. From your description, it does sound like a scratch build proposition. The large fuselage section also does a lot to control it during single operation. Looks fantastic and you should submit these pictures to rcwarbirds for display in our pictures of warbirds. You should be very proud. Good Luck, Twinman"
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Question 20: "Would two OS-91 II pumper engines be a good choice for VQ's new P-38? If so would you recomend three blade 14x7 props be a good choice to fly this bird? please answer this email. thank you Eugene Jensen. "
Twinman: "Eugene, The prototype will fly with 14x7 inch props and two stroke MVVS engines. They turned at 9200 RPM. Will keep you posted on flight characteristics. The plane is not really that heavy, do not have final weight, but your proposed engines will do fine..Now, for the usual nag. If you intend to invert, add glow drivers. You do not want to think about a flame out. Uh when you get the model.....note that four strokes are not that affected by back pressure....can you say scale exhaust outlet?? Just a thought. Send pictures.
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Question 21: "I have been flying for a while. Built a lot of airplanes and like to scratch build. I want to build a B-25 or a B-17, the ones from don smith plans. Do you think I could handle it."
Twinman: "Hi, Well, you may not actually like my answer. Get a cheap twin or bash a single into a twin and learn the flying characteristics first, before going to a warbird twin. Been there done that and made that mistake. Yes, I am sure you are a good pilot, but multiengines are different and much more expensive to build and replace. I do not own a B-25, but I understand that they fly well and are more tolerant of single engine failure. Good Luck, Twinman "
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Question 22: "Twinman! From out of the Past....you would think I would have learned something. I'm just slightly Older than Dirt..and of course had a little bit of twin engine experience. Long About Reed Days and a Twin Flat Top Stoamer...and Twin SkyLark. But since reading your "Don't Do Twins" articles have of course been "Bitten by the Lightning Bug" In your experience's with the SuperTigre .90 and the ASP 1.08 carbs have you established any ideas as to the Fuel Consumption yet? And are you using pressure feed or pumps? Am thinking of using the standard ST .90 carbs and retaining the normal reliable fuel feed that they seem to have. Though I would like to use the Master Airscrew 3 blade 14 X 7 if possible which is just out of range for the ST .90 with the Standard ST carb. Anyway the fuel consumption would dictate the size tanks that I can fit into the nacelles. Right now I can fit in 16 oz. tanks but that is the largest that will go in.
My P38L research is from SuperScale Three Views and would in the finial, end up with a 94 in. w.s. and a fuse length of 63.5 in. which equates to a very similar sized P38 once done by Col. Art Johnson. Which I do have an original set of plans to also use as a guide. Projected weight would hopefully come in at about 14.5 lbs. I have the Center Fuse done and am mounting the retract nose gear in place. Will start cutting and the assembly of the wing today. Should have jpegs available along about monday on a so far basis. Ever seen the Orion built in to a Twin? It's was an Awesome Aircraft! Thanks for your kind consideration. Doug in Denver "
Twinman: "As far as fuel consumption, I cannot tell you that with and without the ASP carbs. I can tell you that I ran the engines for the Morris VQ P-38, the MVVS .91's with the Master 14x7 three blades and saw 9200 rpm max. More reliable at 8800. I did not get time to test with the ST 90, but the carb std and ASP are much larger on the ST than the MVVS. Per other posts on the ST engines, they produce the most torque with the rpm at lower levels similar to above. You will not be using full power with this set up other than take off, so 16 oz is just fine. I use that size on my converted US 1000 with two ST 90's and like it just fine. Good Luck, Twinman"
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Question 23: "Hi, will os.32 sx 2 strokes work well with my VQ A 26 invader. They are rated at 1.2 bhp each. Thanks, Scott Morgan"
Twinman: "Hi Scott, Sorry about that.......job that supports this hobby keeps me running. The Magnum .52's four strokes, with three blade props, is not enough with on board glow, and retracts. While the OS .32's show a lot of HP, this is at rather unrealistic rpm levels and are most of our engines. Based upon the two I have flown off of concrete, I would suggest at least good .45 two strokes and two blade props. This is worse is take off is off of grass and retracts and on board glow, and big batteries......get the idea? While I never suggest overpowering a twin to others ( I do it all the time), it can help with getting out of trouble and flying, or at least maintaining altitude, with one engine out. The first one I flew with TT .36 engines and APC 9x6 two blades took off much better, but single engine is very marginal to maintain altitude. Again, this was done off of concrete. I also did not have on board glow with this plane. Loops require some nose down action to build speed. Hope this helps. The A-26 will snap roll at the loss of an engine as will most twins and of course worse on a warbird, but is relatively easy to correct due to the large rudder.....you do fly with rudder don't you?.....no,,,,,,learn.....sorry on squeaky soap box again. Good Luck, Twinman"
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Question 24: "George, Thanks so much for sharing your experience, I fly a Thunder Tiger P-51 with a low pop O&S LA40 It is a great flying plane, simple, cheap, files good, It is a 20-30 size and with a low pop 40 it honks, this plane, engine combination is VERY reliable, it just won't quit in the air. Would it make a good kit bashed twin? F-82?? I don't care about retracts or If the scale model
airplane police come to my house to get me,I just want a good flying reliable twin!!! You seem to stress engine reliability as the key factor in a twin. This engine is detuned to do just that, small carb. and ports, I could build the center section no problem,do you see any problems???? The current span 53.5 and would be about 73" as a twin. Thanks for you help. Tom Cade
Twinman: "Basically what you see in the World Models F-82 is exactly what you propose and I understand it flies well. My favorite fun twins are these twin fuse bashed versions. Keep the fuse's close together and it will be safer on one engine. The truth of the matter was that the F-82 was not two Mustangs, but a new plane, but if you can keep a secret, so can I. Suggest that you review my posts on bashing into twins. I also suggest two servos for the elevator and two for the rudders. This will be very aerobatic. Make sure the wings are strong enough as the loads go up. The extra wing length is good to reduce the wing loading. My two cents, go for it and you will enjoy it!!! Send pictures. Twinman"
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