8KCAB-inactive

I appreciate all the time you're giving to the subject and what you are saying makes perfectly good sense to me. I watched the video from RC Guys and their airplane does not seem underpowered. The full scale SD is 180 horse and is a handful to fly. I cannot hold it inverted with one hand and slow rolls make me sweat because it is so much work. If you can fly this airplane well you can fly any areobatic airplane well. Having said all that this airplane performs like a trainer compared to the Eagle and the Pitts because it is a trainer. I think i will go with a 50cc motor simply because i can always pull the power back but you can't always push it forward.

Is anyone flying this thing yet?

Dart373

My Feedback: (2)

Good Boy... I am throwing a DA 50 in mine. Gonna order it tomorrow....

tomfrazier

Hey Guys,

Received my Decathlon on Saturday but haven't had a chance to work on it yet.

What's the largest prop that will comfortably fit with the stock landing gear and wheels? 20", 22", 24" inch or what???

Thanks,
Tom

Dart373

My Feedback: (2)

Another site said 24" is close. I think you could easily run a Menz 22x8 . That's a great prop for a DA 50.

cmoulder

I have a DA-50R and Jtec pitts muffler in need of a home, but looking at the firewall it appears that the Pitts muffler is not going to work without major surgery, and it's going to need a pretty big hole for the carb which will extend into the cabin significantly. Is that going to be a problem? I can see that a Brillelli, Fuji or Zenoah might be a better choice in this application.

Looking forward to seeing how you guys do it so I can benefit from your experience when I assemble one of these birds.

Yep, at around 1600 squares this is a 50cc airplane, and I'm also thinking of putting smoke in it. I was seriously considering the RC Guys Pitts Special, but the hideous Easter Egg color scheme put an end to that!

sebo

I hope I am understanding what you mean by "orange color scheme". That is, if it is the muffler you are talking about and it is painted or made orange I would suggest that you get spray paint at the hardware store or auto parts store. They have high temp paints for engines and bar-b-q grills. I have one muffler painted white and it works fine. Do not prime.

Dart373

My Feedback: (2)

Depending on the firewall to cowl/spinner opening.... if it is long enough, 3" or 2.5" standoff's will allow you to runa JTec pitts style canister muffler which I really like on my Extra. Quite and makes good power. With stand off's in the 2.5" range, that allows that muffler to hide under the stand off's. Nice design by JTec.

cmoulder

I hope you're correct, but it just has the flat firewall and no motor box sticking out like most Extras have, with the space underneath. Just a WAG but it looks as if the DA-50 will need very short stand-offs.[sm=confused.gif]

Can't wait to see some pics of a DA mounted on the nose!!

P.S. I just read post #65 that says distance from firewall to spinner backplate is 6.25 inches -- short stand-offs indeed!![X(]

Dart373

My Feedback: (2)

Well, then I wonder if a ? header and a canister with a front dump out will work? Recessing the firewall would be a little bit of a project, but hey, I love this plane and it's been needed in our community for many years!

sdossett

Build update:
- tail goes on nicely I LOVE the hinge type, drilling and quality
- fin had a 1/32nd or so gap between it and the stablizer during assembly..since the LE of the stab was already below the exterior of that part of the fuse. I decided not to lower the stab further but to get it seated well and then ran a little epoxy into the gap..looks fine
-planning on delay of window installation till the very end
-glad I went w/ putting the main gear struts on early..w/ th tail on it's starting to come alive and is real stable on the table... this is going to be a beautiful airplane
Next:
- control surfaces in the rear (my first pull-pull rudder)
- mounting the Saito

Peace

Dart373

My Feedback: (2)

This is an email from Dan. Man, I tell you what, these guys have excellent communications with customers or potential customers (me). Here is what he said about the firewall.

Keith,

The firewall to prop backplate distance is 6.3". DA says the engine is 6.7" long (firewall to backplate?) so you might want to use a Zinger 3.5" aluminum spinner that has the backplate recessed 5/16".

Regards,

Dan Speers
RCguys.com div. of Mobile Airships Inc.
tel 519-756-1110

cmoulder

Dart373, seems the DA-50 dimensions are a bit ambiguous because we don't know where they're measuring from, and in what configuration (with "standard" 3-inch standoffs??), so I got mine out and measured it.

Looks as if it will be an easier fit than I had assumed, and that a near-perfect fit can be achieved with 2.5-inch standoffs. Maybe a little carpentry on the firewall for carb clearance. Just test-fitting the Jtec pitts, it ain't gonna work... lots of overlap into the firewall. Well, in that case I would just use the simple side-dump muffler because the can would weigh too much, and the smoke will add about a pound or so.

Dart373

My Feedback: (2)

Looks like our DA's will work just fine, it is finding a small pitts or... that gawd aweful loud standard muffler that will require the whole side of the cowl to be hacked off. I will make a pitts in the shop with the tig welder before I carve out a 3"x2" opening for the standard DA muffler... Thanks for the info. Looks like our motors will fit!

cmoulder

Hmm... I don't know if the standard muffler would require a lot of hacking. The same post (#65) said that the cowl is 8 inches wide and "7 or 8 inches tall", which might enclose it easily. The distance from the centerline of the cylinder to the exhaust face is a smidge over 1.5 inches, which leaves about 2.25 inches to work with comfortably, assuming the 8-inch width figure for the cowl is correct. The cowl is straight down the sides, so that could work out nicely.

Could one of you guys who has one confirm that cowl measurement?

You're right, they are quite noisy, but that isn't a problem where I fly. I think could figure out how to make a smoke coil for it.

Here is the standard muffler, from the Chiefaircraft website:

Dart373

My Feedback: (2)

Is it really that wide???? Awesome... It may work afterall. Just looked quite narrow. I tell you what, I think I have a standard that I put a coil in. If you want to trade, I will I am not running smoke. Keith

cmoulder

Actually not a bad idea, Keith! But I didn't get the muffler yet, so I'll have to order it next week, when I'm ordering a few other things at the same time. Already got the servos, receiver and some other electronic pieces such as Smart-fly kill switch and Equalizer II for the elevator. (Gradually amassing the bits and pieces so it won't come as too big a surprise/shock come Hanukkah time, if you know what I mean.)

Dart373

My Feedback: (2)

It is FAR less painful to buy it in bits. We don't want to know that we have $2000 in a toy Decathlon!

bonnie

My Feedback: (2)

Well was going with a DA50, but just ordered a Hacker A60 with a 77amp speed control. Will run 10 cells at 5000mha. This set-up will have 24lbs of thrust at full throttle, total weight is under 3lbs.

Kit came on Wednesday, everything looks good, not happy with the fix of the hinges,way to much materiel removed from the holes,also there's a good sized gap under the rudder where it meets the elevator. Did anyone get instruction in the box.

bjboise406

My Feedback: (1)

BONNIE, INSTRUCTIONS ARE ON LINE ON THE RC GUYS SITE. SAME COCERNS YOU HAVE WITH THE HINGE FITS. FILLED MINE WITH GLUE, HOPE LIKE H___ THEY HOLD. GOING WITH OS 120AX. 3.4 HP SHOULD BE PLENTY. THIS IS NOT A 3D AIRPLANE. GOOD LUCK

mobyal

Same concerns w/ hinges and control surface gaps. Though all the surfaces and trim lined up, there was quite a gap in all surfaces. Sent RC Guys a note and heard back promptly. They said that's the way it's supposed to be and flutter's not a concern at the speed this plane flies. So I put them in, using plenty of epoxy. They seem good and tight; I can't pull them out! I did seal the gaps in the elevators and ailerons, tho.

Dart373

My Feedback: (2)

I would still seal the gaps no matter what! Can't hurt, but gaps can't help!

mobyal

That's what I was thinking. I may even do the gap between the rudder and vert fin, too, but w/ different colors it'll be sort of a PITA.

8KCAB-inactive

There are gaps in all of the full scale airplanes control surfaces. Aileron gap seals are offered by the factory as an option. May I ask why this is a concern? This is my first 1/4 scale and I'm not sure why this is an issue. Any help?
Thanks

jbarnes

Mine flys fine with the factory gaps. My 100cc Yak has the hinge lines sealed but for the general flyer the Decathlon is I find no issues. Is someone noticing flutter on the control surfaces on this plane? Thanks, Jerry.

mobyal

Sealing the gaps makes the control surfaces more efficient, as it keeps air from leaking through those openings rather than passing over the entire control surface. Or so I've been told. How much more efficient of course depends on the individual model. Obviously a fast aerobatic airplane needs/will benefit from gap sealing more than, say, a J-3. Sealing also helps prevent control surface flutter. I raised the flutter issue w/ RC Guys, and they told me that at the speeds this airplane flies, flutter won't be a problem. Dan at RC Guys did say he'd sealed the aileron gaps on the prototype to make for a better roll rate. On this airplane it probably doesn't make a whole lot of difference whether or not the gaps or sealed, but in the final analysis I decided that if nothing else it'd make it look better to seal them. How's THAT for aeronautical reasoning? LOL
Al