Widget

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I haven't read all 852 posts, so my appologies if I am re-hashing an already covered topic: Engine Out Procedures. My first DA, which was my first Twin, was lost, plain and simple, to lack of experience/engine-out technique. With that said, please explain the right way to do things when, say, in level flight, and the left engine dies? One of my questions is, can you turn away from the dead engine, or turn only INTO the dead engine? I tried to turn away and only went straight until I probably got below minimum speed and she lawn-darted in with no control at all. I did recognize the engine-out right away, and flew straight and level for a ways, but lost the battle in the end when I tried to "force" the turn around with more and more rudder. thanks for your help!

boingram

Widget,

NEVER turn into the dead engine...she'll flip on her back. Opposite rudder and try to stay out of the airlerons and they create drag.

One of the problem with the Sual Ace is the small rudder. I am assembing my third and I'm going to increse the size of the rudder. Antime I had an engine out on my other Dual Ace's, I would shut the good engine down and land dead stick. Not optimum, but better that lawn darting into the ground.

Bo

Widget

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Hey Bo,
Ya know what? "Something" told me NOT to "turn into" the dead engine. I'm a full-scale pilot (single engine land) and could have learned some twin info along the way And you hit the problem on the head! I had little rudder authority, so straight and level was all I could maintain. I got 1 1/2 flights on my DA and was already SO in-love with it that I am buying another asap. But, this time (and because my middle name is BASH), I'm doing away with the tail and top spine and going with a B-25 style tail so the authority will be in the slip-stream of the prop-wash(s). Wadda ya think? Also, I am currently designing an "ERS", or rather Emergency Recovery System with a retract servo operated parachute (possibly with a retract-gear possitive deployment mech) and elastic shock-cord attached to the aluminum spar mid-section. BTW, I am running 46FX's with 11X7 APC's in a tail-dragger config since I fly off my own dirt runway. You can see the last DA's Demise at:::: http://www.youtube.com/watch?v=OKpc4teuXdc

boingram

Widget..great video and I love the tail dragger config. I'm gonna put retracts in my next one and this would eliminate having to cut up the nose. Can you post some pics of that mod...did you change the cg as most folks have...it should be 90-105 mm instead of what the manual says. As it comes with the recommended cg, it's WAY nose heavy...much better with the 95-105. This will be confirmed by the extenive posts on the subject.

The DA is a great airframe. I have now and have had many twins and this is one of my favs. My new one will be stripped/painted a better color sceme...Bo

Widget

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Thanks! All I did for the TG mod was fit and epoxy a hard-wood block in the fuse tail before any assembly and used a Sullivan tail-wheel assembly with the spring up into the rudder. For the gear, there are 2 formers a little forward of CG that I epoxied 1/8in lite-ply between them, sandwitching the fuse balsa inbwteen that and the landing gear itself. CG was right at 100mm I believe. That, or 105. As you saw, I have to fly everything TG or the dirt/rocks from the nose wheel and lower clearances will EAT my props. I actually built the DA the first time TG with retracts, but they were just "not right" and too heavy (LARGE Hobbico mechanicals) and thus you hear me in the video upon first take-off with the fixed gear say " Much better!".... With the B-25 style tail-mod, I will have to run a pull-pull tail-wheel. Rudder control system "to be announced"... (-: Hey! The sun just came out here in Origun (a local miracle indeed!) and I have a brand new Super Skybolt ARF wanting airborne..... later!

Yakflyer

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Sorry to see you loose one Steve. I am about finished with my DA. Installing Spring Air Retract system one mine.

Widget

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Yakflyer, I live by the saying(s), "If ya don't wanna wreck 'em, don't fly 'em", or "If ya ain't wreckin', ya ain't flyin',,,,, If I got upset about crashin', it wouldn't be a "hobby" any longer. And too, I ALWAYS look at a crash as another oportunity to build.... I'm quite happy doing both...

Lefte

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Howdy everyone,
I just picked up my second DA this fathers day and forgot how much I miss it. The first one was an engine out hit the fence disaster, wish I could show a movie, but none was taken. I have a video of the twin engine start and burn in and will post shortly. Just wondering why I would make it a tail dragger over the set up it has now. I read earlier that it was changed because they took off on a grass/dirt runway. Can anyone please elaborate?

Thanks

Lefte

Yakflyer

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Left Thumb,
I can only speak for myself, but making the DA a tail dragger can be a plus if you use a grass/rough run way to promote better ground handling capabilities. I just finished my DA and took her for a maiden flight this past Sunday. Boy she is a lot faster than I thougt it would be.
I am using a tricile gear spring air retract system. I tossed the arf tires because they were not hard enough for my grass runway and put some dubro hard rubber tires on. You will need to be ready on the rudder stick to keep it on line. I use a little up elevator while gaining speed to keep the front end from bumping around too much.
I installed a a pair of TT-46 Pro with Mac tuned exhaust pipe with 11 x 7 props. I am getting 14,000+ Rpms at full throtle. Wahoo!

I forgot how much your blood pressure goes up when you fly a dual engine aircraft. I only got her up to 3/4 throtle. She was very fast! My knees were shaking a little after landing. Lol. But that is why I am in the hobby in the first place!

I was very impressed how light it landed with a reasonable roll out. I was prepared for a fast landing but worried too much I guess. She was a kitten on final.

A friend took some video footage. Hope to get a copy to post.

Here are a few pictures. I could not get the nose cones to balance so I tossed them. Order a pare of true turns. Should be in any day now.

Lefte

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How do you think it will fly with to Evo 40's?

Sandmann_AU

Mine flies just fine with a pair of Super Tigre 40's. Admittedly it doesn't leap off the runway - it's more of a scale take-off, and touch & goes need a bit of care but once airborne it scoots around just as nicely as you'd want a civilian twin to scoot, but if you're thinking of hacking retracts into it you might want bigger engines, to pull the extra weight around.

As for converting it to a tail dragger, I really don't see the point. I fly off a grass strip and the DA is great on the ground, far more so than either of my tail dragger planes. If you really wanted to do it you'd need to move the main gear forward about 2 inches, which would have it mounted on the fuselage. That'd mean lots of extra bracing forward of the CG, and extra weight isn't what you want when you're running at the low end of acceptable engine size. Besides that, you'll end up with all the problems that planes like the DeHavilland Mosquito etc had - twin engines never spin up at the same rate and once the tail wheel's off the ground you'll need every ounce of rudder to keep it in a straight line even if you're headed directly into the wind - worse still if you have a cross wind. The DA's don't have much in the way of rudder... only about as much as the average trainer, and there's a reason planes like P-38 Lightning, Messershmitt ME110, B-25 Mitchell etc all had dual rudders. I do agree that the ARF wheels need replacing though - I put 2 1/2" dubro wheels on the mains and a 2" one (along with a Fults dual strut nose gear) on the front to help smooth out the bumps. Set up a mix for a little throttle steering along with the rudder and you'll have excellent ground handling and effective yaw control for cross wind landings (it helps pull the outside wing around in stall turns too). I also put on-board glow on mine to help avoid low rpm flame-outs (often fatal on twins). With the batteries for both the radio and glow in the nose cone mine balances with no extra lead. I'd like to see these planes with flaps for landings on calm days, but even without them they're not much harder to land than a trainer.

Yakflyer

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I should be okay. I have few of those type engines. Like the TT-46 Pro Series, they are dependable. I would make sure your prop selection is a match for good RPMs (12,000+). My TT-46 Pro's get 14,300 rpms at full throtle. Be careful not to run your engines to lean for fear of an inflight shut down. I leave mine just a couple clicks on the rich side for safety margine.

Don't be too scared when you balance your DA if you have to add 12-15 oz to the nose. I had to add 15.35 oz to achieve proper balance at the back end of the CG range (95mm) more maybe needed is you want to set the CG at the front end (85mm).

Another item to put in your thinking cap is to have each engine servo on it's own channel. I am using a Futaba 607 2.4mhz rcv with a Futaba 9 Caps transmitter. The reason I chose to do this was to be able to dial in the end points as close as possible for each engine to react exactly the same. If one of your engines runs a little faster after you have finished your setup, richen the faster engine until the RPMs fall close to the slower engine.

If all goes well, you should not have to adjust the faster engine more than a few hunderd (+/-) Rpms to be in synic with each other. Boy, does it sound coll once you push the throtle up!

Have fun!

Yakflyer

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Sandman,
I agree with your notes. But your commint concerning 'hacking it up' with retracts. Ouch! lol
Bet my plan will look cooler than yours on a low pass! lol

You know, I thought about the flaps too. But in the end, you always bring it down. Just a matter of how fast/hard you decide to bring it down. (snicker)

I don't know if you ARF had the suppliment for the nose gear. Mine did and they recommended to double up the nose with another piece of light ply so the nose gear does not rip off with a hard landing.

I agree the rudder on this plan has minimal effect. I did program about 10% rudder with my ailerons for smoother turns.

Lefte

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Here is the video of the engine run up...
http://www.youtube.com/watch?v=etnzG...eature=related

Sandmann_AU

3 blade props on evo 40's? Interesting choice... what size are they, and why'd you go with them?

BTW if you don't have one already the twin's a great excuse to get yourself an optical tacho... they're not absolutely required as you can tell from the sound when the engines are in synch, but it does help to "tune your ears in" if you're not used to listening for it.

Sandmann_AU

Yeah true... but my plane looks cooler in the air than struggling to get off the ground coz the retracts are to heavy for my baby engines. I'd love to put a pair of 52 four strokes and retracts in the DA but it all gets too expensive for my mortgage-stressed pocket.

I've got flaperons set up on mine but they compromise the ailerons too much for my liking. They're ok if you have a perfect landing but if a puff of crosswind rolls the plane on approach with the flaperons down it takes a lot of work to bring it back to level - besides with the amount of wing this plane has it really doesn't need them. I did end up putting real flaps into another plane that came without them - a Harmon Rocket 3. It always had really hot landings as it has stubby little wings with big fat airfoils and would tip stall when it got near landing speed. Now I start my approach higher with full flaps and throttle just above idle, let it come down at about 45 degrees glide slope, blip the throttle to flare the plane and it basically lands itself. They really helped there, but the DA practically glides itself in.

No, mine didn't have that... it's probably not a bad idea either. When I put the Fults strut on I had to move the upper mount higher on the firewall so the force is spread over a larger area which should help somewhat. I wonder if the firewall is breaking (in which case the extra ply would help) or simply tearing out of the fuselage in one piece (in which case it wouldn't help). Hopefully I'll continue doing landings that aren't hard enough to find out.

Have you played with throttle steering? Aileron - rudder mixing only works while you're actuating the ailerons so as soon as you've established your bank and release the ailerons you're releasing the rudder too. I use A-R mixing on my Skybolt because it's got some quite noticeable yaw coupling and the mix lets me sort out the bank before I start needing the rudder, but the DA doesn't so I just thumb the rudder manually and the throttle steering assists the minimal rudder. It also works really well on that turn onto final... I tend to avoid banking too much on that slow turn and try to make it a fairly flat one so the throttle steering helps pull the outside wing around.

Widget

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I fly off dirt, so I build or Bash all my planes as tail-draggers for 3 reasons: 1: to keep the prop(s) up out of the dirt as far as possible on take off and landing, 2: to keep the nose-wheel from kicking rocks into my prop(s) and 3: because they LOOK SO COOL.... If you will watch the Youtube vid that my Flyin' buddy posted of my (past tense) tail-dragger DA, I spent the first few minutes of the DA's life "gunning" the motors to see if one would come up before the other. BOTH engines, every time, never hesitated even once, so I do not subscribe to the adverse yaw that "can" happen if, IF, the engines are tuned correctly. Keep in mind about flaps or flaperons; Landing 'hot' gives you much more control, should you lose an engine, than landing with flaps at just above stall speed. My particular DA was not controllable even at flying speed other than straight and level until she slowed, rolled over and then did her death-dive. Lack-Of-Experience was a major factor on MY part, but losing an engine while atempting a go-around would be fatal to almost any pilot of the wee little twins under any circumstance, eh? And yes! They ARE knee-buckling, heart pounding FAST !!!! [>:] I fully plan on building another DA as soon as my therapy for post-tramatic after-crash depression and mental shock is completed, or, in other words, when I am ready to crash another one! Oh yeah! As to added weight? The lite-ply landing gear blocks I add usually weigh about as much as the nose-wheel assembly I leave out, so it's a wash.

Lefte

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Matt,
The reason I went with the tri props was because of the engines I ordered. The evo beginners model. and they came with the thi props. Let me ask another of many questions to come. When I am building and putting the ailerons in I noticed that the cover will of course go either way. Does anyone think it matters which way they are set?

Lefte

pc55bomber

Hi Guys
Here are some pics of my DA sporting a new colour scheme which looks better than the original I reckon.
Cheers
Paul

Sandmann_AU

You're probably better off getting some two blade props for those engines. I know the prop you're talking about - I have a P51 PTS trainer downstairs that house that I repaired for a friend that had the same motor & prop - they're pretty rubbish props. If you really want to stay with the three blades, get some half decent ones.

As for the cover you're talking about - I assume you're talking about the engine nacelles? If so, from memory there are definite top and bottom halves, but left and right are the same.

Sandmann_AU

Heya Paul...

That red trim really looks good on the DA. Very professional looking job you've done there too - looks like it was factory done.

pc55bomber

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Heya Paul...

That red trim really looks good on the DA. Very professional looking job you've done there too - looks like it was factory done.


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Thanks Matt, just changed the 3 bladers from Master Airscrew 10x7 (too many Revs) to Graupner 10x8.3 and it really hammers.
Pity there is not a bigger range of 3 bladers available as a 10x7.5 would be ideal.
If I had the ground clearance then 11x7, 2 blade is the ticket.

The 2 four strokers sound fantastic.

This DA is my twin trainer before I get into my ESM B25 Bomber.

Cheers
Paul

Sandmann_AU

Hehe I know what you mean re: the small range of three bladers - I've squeezed an FT-160 twin cylinder into a GP Super Skybolt and had a 16x10 2 blade prop on it but it kept eating dirt when I landed... trying to find an appropriate 3 or 4 bladed prop for it's a nightmare. I eventually settled on a 14x9 MAS 3 blade (which I've yet to purchase).

Y'know... I used to describe the DA as my twin trainer before getting a De Havilland Mosquito... but the DA's so nice I haven't been willing to strip it to build the Mozzie! Guess I'm just gonna have to save for new electrics and engines, and have both.

Lefte

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Excellent Pictures Bomber...

Sandman, the part I'm talking about is the covers for the servo for the alerons...Any info?

Yakflyer

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Left Thumb,
I believe the rule of 'thumb' (sniker) is to center the aeliron control horn as close to center of the control surface, which I believe will be installed with the servo arm cloests to the wing tip.
If anyone else knows better, please do share if I am not correct.