I have built and flown only two twins, both from the Pilot Twin Ace kit. These are 60" span low wing sports models for 19-25 2-strokes. The only deviation from plan was to build out thrust into both engine installations. Both weigh 5-5 1/2 lbs.

No 1, (in 1985) was with 2 x OS 25 FP 2-strokes and the supplied 4oz tanks giving about 10 minutes duration. Being totally absorbed in flying often resulted in an engine out situation as one ran out of fuel.

No 2, (just finished) with 2 x OS 30 4-strokes and the supplied 4 oz tanks. Several engine cuts to date.

Performance with engine out.
Fast, slight yaw and roll compensated for with 1/2 opposite rudder.
Slow, severe yaw and roll, compensated for with power to idle, nose down and rudder.

Crashes (so far)
1. Heavy landing after single engine go-around (never again) bent nose leg. Model 1

2. Heavy landing after applying slight power in a single engine landing. Dropped a wing, recovered, stalled and almost recovered. bent nose leg. Model 1

3. Crashed after engine quit during low pass. Applied full power to good engine and attempted to turn into good engine to line up with strip. Model flicked out of the turn, stalled and failed to recover before nose down, wings level crash. Tore out the poor nose leg and broke front wing dowel. Tail unit separated from fuselage. Model 2

4. Heavy landing after aileron jammed on fuse side (wing attached incorrectly). Did a very exciting circuit using what aileron I had to correct roll and steering with massive amounts of rudder.
"Arrived" wings level in long grass alongside strip. No damage.

Lessons I have learned.

If one engine sags or dies at low speed, low altitude, kill the other engine and treat as a normal dead stick landing.

If the same happens at altitude, set up for an emergency landing using minimal throttle then kill the bloody thing to remove the temptation to stretch the approach.

Do not attempt to squeeze maximum rpm from the engines. If you need max power, get bigger engines.

Do not try to lean out a slow engine to match a fast engine.

Have fun.

These are my experiences with my two small models, hope they have been of interest.

Col

I think one of the reasons the Twinstar was so popular was it engine out handling.

I for one, think that RealFlight G2 is much WORSE than the real Twinstar. I've had more than my share of 'flameouts'. I'm running ThunderTiger PRO's .36, i.e I'm way over powered. But every engine out has been a virtual non-event... power up, turn away from the dead engine -- or not, the Twinstar just felt like she was out-of-trim with one prop stopped.

I just had my Twinstar out this weekend. What a fun plane, I fear its too easy to fly and is teaching me bad habits for when I eventually do get a KMP P-38 or other less forgiving twin.

Good thread! At present, I have about 20 flights on my 60"WS, prop driven twin .25 A-10 and out of those 20, I have had 3 "half" deadsticks. Having read Keith Sparks' article in MAN a few years ago, he mentions that with the engines behind the CG and so close to the centerline, an engine-out (on the A-10) is more of a nuisance than a control problem. When it occurs the aircraft behaves as if the rudder or aileron is out of trim and although it may not have enough power to gain altitude, one engine will be able to bring the ship back into the pattern and land safely. Flying my A-10 and experiencing the engine-outs, mine behaves in exactly the same manner. On one occassion, as I reduced throttle in prep to land and on downwind, I noticed it was handling rather sluggish and it didn't even occur to me that an engine had quit. Upon final approach was only when I noticed the right prop wasn't spinning and I let out a rather passive "huh." And that was that. Landing was fine and almost felt I would have had enough power to go around again if I had to (but didn't).

To fullfill the original query of this thread, this A-10 has flaps, no gyro and the wingloading is about 32 oz/ft. Despite the heavy wingloading, the A-10 flies amazingly slow w/o any indication of a tip stall.

And to add one final thought: Discussing twins at the field, I'm told it helps to offset thrust of the right engine MORE than that of the left esp. on conventional wing mounted twins with non-counter rotating engines. Makes sense, right?

And of course, if we all built Cessna SkyMasters we wouldn't be talking about this!

Ted

To OldRookie
Go to page four of this forum and I did two post on using gyros on airplanes.
Good Luck,

Twinman,
Thanks for the heads up on your post on gyro use.
When people say to learn to fly with the rudder, just how much experience is needed to successfully fly a twin in an emergency situation? I use the rudder for take off and landing, and for some maneuvers, but that is about it.
What type of things would I have to practice to get my left thumb into the picture, and conditioned for that engine out on a twin situation?

Greg

You must fly with coordinated rudder if you have a gyro on it. If not, the gyro will fight a turn, just as it will a cross wind condition.
My two cents is to learn to fly coordinated at all times. The reaction to an engine out must be automatic and not thought about,,( OK one engine out, now I must use the rudder as I do in landing.......SMASH!!!!) opps.
Good luck,

I agree Twinman, but my first reaction is cut throttle then apply whatever is needed to keep it level for an emergency landing. I haven't used a gyro on rudder as yet but I do contemplate it after every scare.

Col

I had a scratch built twin called a ".50 Caliber" from MAN plans. Basically, it was a twin .25 powered smaller Duellist. This was a very, very nice flying twin. I didn't loose an engine often. In cruise flight, the only way I knew that an engine was gone was from the sound. The aircraft continued to track straight and true. At slower speeds, there was a definite yaw, but easily corrected with just a smidge of rudder and a bit of aileron to pick up the low wing. Easily manageable. The airplane eventually died of "Dumb Thumbs" with both engines running sweetly. I'll have to build another some day. I really liked that airplane.

To SeaHawk

I was not clear. You are of course correct in handling the emergency of engine out. I was refering to normal flight characteristics.
The flight characteristics of gyro assisted flight, is that you must use rudder during normal flight.( With it on the rudder)
The gyro is not an auto pilot. The characteristic is a gyro on the rudder ( And possibly on the ailerons) is that instead of the instant snap roll of some planes with engine loss, the gyro dampens the yaw and resulting wing rise on the live engine, giving you time ( We hope) to react by getting the throttle down,NOW, and getting sorted out. This is much easier than getting out of an unexpected spin.
Again, a gyro is not an auto pilot. If you don't react, the plane will still go over, but it does dampen the actions to a level that is MUCH easier to handle.
Good Luck,

Engine-out on a P-38:

I think another characteristic of a P-38 that contributes to it's problems when an engine quits is the airfoil at the wingtip.
I suspect the narrow wing chord and the taper can add to the problem. I would think that adding washout, along with differential aileron (applied sparingly at lower speeds), could help the engine-out situations, although it would cetainly not be a total fix.

Curious . . . if any of you have done this as a retrofit operation with your P-38's (or other warbird), did this affect your engine-out situations?

Regards,

Al Parry
[email protected]

For Twinman,
When you talk about coordinated rudder, do you mean to say that when you bank right or left with ailerons, you want to use a bit of rudder and up elevator at the same time? Also, I have an FMA Co-pilot gyro. (https://www.fmadirect.com/site/home.htm) It has proportional control set up with my transmitter switching on or off in flight and has the elevator and ailerons servos plugged into it. My question is do you think this gyro is a good choice for the P-38, using coordinated rudder or should I use one that works the rudder servos also?

This may be a dumb question to the veterans out there, but specifically on the P-38, don't the engines rotate in opposite directions? Which is best, rotating in or out? Also, which engines can you buy and modify to rotate in opposite directions? Does the opposite rotation in one direction or another help with an engine out condition?

I think the first model of the P-38 had engines that rotated in the same direction, and it was changed to opposite rotating for the others. The main benefit of having the props rotating in different directions is that the engine's torque balances each other out during the addition of power, alleviating the dangerous torque roll. This would also make rudder input very minimal on take off. As far as engine out conditions, I suppose it could make a difference. Any full scale twin pilots out there wish to comment? I don't think it would make a huge difference with our models. You can modify any engine that has a removable front housing (where the carb is mounted). Remove all the screws, and turn the front housing 90 degrees. Unfortunately, I can't remember which way! This is kind of critical, so hopefully somebody else can answer. Put the screws back in, mount a pusher prop, and you should be good to go. I have never tried this myself, but I have seen one run quite well. I believe it was an older Super Tigre .60.
Good Luck.

Baringer and vonJaerschky:

This bit about engine rotation has been covered many times in various threads here, but it never hurts to repeat it.

Opposite engine rotation is highly desireable on a twin, and if it can be had, is well worthwhile.

The left engine should be conventional rotation, making the torque tend to roll the plane to the left. This way when the right engine quits the offset left sie thrust is countered, to an extent, by the torque twisting the airplane in the opposite direction. The right engine should be reversed, with torque and thrust also reversed. This gives the best engine out performance, and neither engine is "Critical."

vJ, I don't think any P-38s were built without counter rotation, but due to airflow, buffetting, and other problems the production P-38 had the props turning the "Wrong" way.

Bi..

I knew I had read somewhere that there was a version that did not have counter rotating props. Seems the Brits ordered some. I think I read it in Squadron/Signals P-38 in Action. anyway, here's a link confirming what I read http://www.aviation-history.com/lockheed/p38.html

vonJaerschky:

Learn something new every day and you're still alive.

Thanks for the link, I had never heard of that special batch for the British without counter rotation.

Thanks again.

Bill.

No problem. It does make you wonder why anybody would order the aircraft without counter rotation, though. Perhaps they thought it would make maintenance and logistics easier. I'm sure there had to be some engine parts on the P-38 that were specifically right/left with the counter rotating parts. Camshafts, etc. That problem would be eliminated with both turning the same way. That hardly outweighs the benefits to the pilots of having counter rotating props, in my opinion.

vonJaerschky:

Most twins are built with identical engines just for the reasons you mention. The Grumman F7F Tigercat for instance. The decision to have both its engines with the same rotation was deliberate, based on parts stock and possible logistics problems.

One of the most successful twins of all time, the Douglas DC-3 and the military C-47 variant had both engines turning the same way. And I don't know of any full scale twins on the market with counter rotation.

Actually, twins with counter rotation are very rare. With proper maintenance, loss of an engine in full scale is extremely uncommon, and the added cost of counter rotation is not justified. This is not the case with our models, not many fliers go more than four or five flights without losing an engine.

Bill.

The Piper PA-32CR Twin Comanche the last version built had CR but in the appropriate direction unlike the P-38. This substantially reduced the VMC and reversed the poor fatality record of the earlier models.


John

John:

Thanks. Didn't know about that one. Knew the Comanche had a pretty bad record, though.

Bill.