Stevo! That's a GREAT looking model! And congrats to you. If you were like me, it was a very nervous time during that first flight. So, all the months, you ahead of me, me ahead of you... and I get mine off the ground just 1 day ahead of you. But don't worry... the day I hit expiration on mine, I'll be sure to immediately post that event so that you can not fly yours the next day!

Now, if somehow yours expires before mine... I guess it would be nice to hear that warning as well because it could be that I haven't flown mine is several days and you might hit that ahead of me. LOL!!!!!! I just couldn't help but think of this after the last few days.

I did more on mine last night and tonight. Lots of little touches and tuning. Lock-tite on LG and Engine bolts, a few more stickers, added the weight for lateral balance inside an aileron servo opening, a few wiring mods and some more tie wraps. I also got my external switches installed. I can now put the model together and have enough power inside for a full day at the field... likely 4 or 5 tanks of gas. I then gave it a really good clean up. It has rained here like crazy. Our grass has grown as the field and so that was trimmed by the prop as well as somehow picking up a bit of mud.

And a discovery! I also have motorcycles. There are some really great cleaner/polishes for plexi windscreens. Having some of this on the shelf, I thought it a good time to try it out particularly due to the Decatlon's large windscreen with grass bits all over it. It worked great! It is good for plastic, paint and just about any surface. It cleans and polishes both. So, it leaves behind a nice slick thin wax finish which, if it works like it does on a motorcycle windscreen, makes it a LOT easier to clean the next time.

I am really happy with my 36cc Brillelli running a 19 x 10 prop. It won't quite hover... or I don't think it will? Maybe when I tune it a bit more and it gets a bit more carbon built up.... but it climbs really quickly. I still might try a 20 x 8 on it to see how that does. My crash pile LG is doing great! It was off of a quarter scale CMPro Katana. It is just a bit wide where it hits the fuse so comes out flat for the first 3/4" or so. But somehow it just looks right. It is some sort of phenolic and is a bit wider and taller (and heavier) than the stock gear. I'm also very glad that I added the 1/4" baltic ply LG plate to the interior. I wish I had used the same for the firewall. I might yet have to do something about that light ply. It crushes way too easy making it hard to tighten down the engine bolts. I worked on this some today. If it remains an issue, I might try some fender washers or something. I wish I could see what is happening on the inside as well. I can only guess the same. I hope I don't ever have an engine ejection! Guddentite for now with Lock-tite and I hope is has settled.

The wheel pants from the LG were sort of busted when I got the used Kat. I plan to use those but they are going to take just a bit of work. The mounts are toast and I need to glass the inside in a spot or two. Since our grass was high, I really didn't want them on there anyway. The bush plane look! And the only other thing to complete is the flying wires. I think I'm going to run by the LHS, which is 30 miles from here.... and pick up some stainless... maybe like 1/4" x 1/16" or so... whatever is pretty stiff, or some more of those Dubro straps to make the mounting points. I have leftover cable from my pull/pull system. I can use some of my small brass tubing for crimps. I'll likely cover the crimp areas with shrink wrap... I have a set of Dubro turnbuckles, however I would need another set and those are small but still weigh a bit. Maybe I'll just try really hard to get the cables very close to the right length and just twist the cables themselves to tighten them up. Perhaps I'll use those turnbuckles on the bottom only and rely on twisting the cables on the top. I'm trying to keep it all as snag free as possible as I need to be aware of the tug line. So far it is very clean back there.

Oh, and my other mod... a Dr. Pepper bottle! [8D] Since I have the bomb bay and it fills about half of the available space in the cockpit below window level.... when working out the receiver I need to lay one of the antennas flat on the top of this bay. The downside is the possibility of wing servo wires dangling down onto or near it. So, I took the bottle, cut it to fit under the wing bolt plate and velcroed it to the bulkhead. This leaves an open ended cannister which is just below the wing and I plan to feed my servo wires into that. If this works out really well, I might have to find myself a 'cheap junkie' pilot figure that I don't mind mutilating. I could cut the top off of his head and feed the wires in there. Would that be a wired brain? I had been using a rubber band but didn't really like that although with care it worked. As trashy as the DP bottle sounds, as it is clear you really don't see it without really looking.

Meanwhile, I look forward to my next trip to the field. I'm hoping these tweaks make it even better. I 'really' would like to get in at least another 8 or 10 flights before we pull out for Joe Nall next Wednesday evening!

OK!!! Aside from wheel pants, my Decathlon is now at 100%! I dove into slicing up a piece of 1/2" x 1/16" aluminum into 1/4" by 3/4" strips and one long one. I rounded all the corners and bent them so that the angle would closely match the angle of my flying wires! I was successful in getting the top wires rigged so that I only needed four twists of the cables to pull them tight. On the bottom, I ran a strap completely across the fuse just in front of the tail wheel. I used a couple of quarter scale Dubro turnbuckles off of this and then cable out to the smaller angled bits. This allowed me to put tension on the whole rigging. It's not a guitar string.. but it has a nice high pitch when strummed! The end result was a very clean topside with no real potential for snagging a tug line. Using only two turnbuckles kept the weight down as well. I'm really happy with the final product.

Meanwhile, I hope to fly again tomorrow evening and hopefully Saturday and/or Sunday. We still have work to do on the trailer and packing stuff up... We should arrive at Joe Nall in the wee hours of Thursday morning if not very late Wednesday night. This will be my first Joe Nall! I hope to fly the Decathlon there a time or two. I will have to be certain that the adrenalin from the whole affair is well under control before I do! I hear they are expecting around 4000 this year! WOW!!!!

Here is my progress so far.

P40,

Looks nice. Ilike the color scheme! All these new builds posted here have me thinking about building mine!

Rick

I managed to get in four flights with my Decathlon at Joe Nall. One was spent seeing how slow it would fly. It sinks quickly, but just more up elevator and it will sort of semi-harrier around quite well at a very low speed. I'll keep working on this as I am still coming in just a bit hot on landings. Seems I rarely put it down without a bounce.

My CoG wound up in the most rearward area. I think I'll stick a big 1800 mah NiCd up near the firewall for my ignition battery and see what that does. It does fly a bit tail heavy. My flying partner absolutely 'loves' the way it flies right now, but he is a much better pilot than me... nearly 20 years of flying vs. my one year... and doing lots of 3d work... so tail heavy to him is a bonus. This model is going to make me a better pilot. At the moment, it really loves rudder. Knife edge is extremely easy. It really likes to be hossed around up there. It seems the more you ask of it, the better it flies.

About the only thing I'm needing to get used to is better ground control. I'm just a little behind it with rudder input and then I seem to overcorrect it. I think next time out I'll just do a lot of ground work with it.

The good news... even under the pressures of flying at Joe Nall, the model is back all in one piece... I wasn't the prettiest flying, but far from the worst I saw. For me, as almost all of my flying is from my home field, it was really good to fly there and learn some more about the different environment... like 'groomed' grass... the very best I've ever flown from. Almost too good. This model is also going to further enhance my stick work, making me use all four inputs more than I normally do and more equally. I am amazed by how it loves to be tossed around aggressively. I'm looking forward to more flights back here at home.

I was going to start a new thread to ask this question, but might as well ask here where we have so many people exploring the different pros and cons of this model. I've been flying my Decathlon for about 2 years now, and am starting to get a little bit of looseness where the wing hold-down dowels go into the former above/behind the windshield. Basically with the wing bolted down, I can move the front of the wing up and down and each wing half side to side ever so slightly. And I do mean slightly...barely a fraction of a millimeter, but it's there nonetheless and will likely continue to get worse. Has anyone else had a similar issue, and what can be done to fix it?

Additionally my windshield has begun to split along on edge (between the windshield frame and the wing). Figured it should be easy/cheap enough to replace, but according to the parts listing on Dynaflite's website they want $30 for a new one.  [X(] Unfortunately I think my options are going to be limited to paying that or making a very visible and unattractive patch to hold it together.

Ihave had the wing dowel thing happen to me on another model. All Idid was wrap the dowels with light fiberglass cloth and soak them with thin CA. Then Isanded them to fit. If you have severe dents, wrap that area first with strands of the glass, CA, sand flush, then do what Imentioned previously.

As far as the windshield, That price is absolutely insane! Ihave made tons of windshields over the years. Check this link and do it the old fashion way.

http://www.sigmfg.com/cgi-bin/dpsmar...FV4.html?E+Sig

Just make a paper template, cut it out and you will be all set. Tower used to carry the stuff. Get the large sheets.

Ihope this helps.

Got a few more flights on my Decathlon. This thing LOVES to be flown hard! It likes horsing around. It loves rudder. I'm still feeling it out myself... and still it has the most value of anything in my hanger even though it doesn't have actually as much money in it as others... but darned... I sure don't want to put it in! So, yeah, I'm being a conservative.

I have noticed my tailwheel tire is not enough. It looks like a car tire with like 4psi in it. Suddenly the ground handling started to get weird... then I noticed the tail wheel overriding the springs and turning the plane like a car with a blowout! I 'might' need to go even stronger with my tail gear... the main spring may be just a little light as well. I didn't use the stock assembly but something a bit heavier... but only a bit heavier. I may be putting a nice CF gear back there next... if the one Ihave will fit the space.

The 36cc Brillelli feels really good on this model. It will climb up there in a hurry. I really don't think I'd like the model with a 26cc at all. Anyway, there's my report for now. Hopefully I'll get a few more flights in on it again through the week. I have played with my flaps a bit but haven't started tuning the elevator mix... so haven't used them on takeoff or landing. Looking for to that as well. Still too nervous with the model to put it into a stall... I guess that should be my next really simple goal. Duh... So far, getting there has resulted in harrier like reponse. I guess stall will be pretty high alpha.

I have alot going on with this model and hope it survives long enough for me to enjoy all of it's potential.... bomb drops, tugging gliders, banner tow, and just getting really good at flying it! It is very easy to just fly around... but I just can't stop with that!

Hello everyone,
This is indeed a wonderful thread. I am just about to start building this kit, and needed to know on which engine to go in for.
I am yet to decide between a glow or gas for this. How much weight could this take on the nose and yet balance properly ?
For gas options, i have RCGF and SPE engines available in 43 CC sizes.. Are they good enough ?
I believe for glow, i would need a 160 2 stroke. But if i would need to add nose weight with a glow, then there is no point of using it.
Gas engines seem to be around 55-65 oz including the ignition/muffler . Do you think this would balance out OK ?
Thanks so much for your views.
-Gaurav

Gaurav,

You will generally get answers based on personal preferences. I am no different. I prefer gassers. I think this kit is ideal for a 40cc gasser. Mine needed the nose weight of a magneto ignited Quadra 42. Others have needed less weight. That size is just about right for power. Much more and you will have problems with prop strikes (18" is just about maximum diameter). Much less and it isn't as much fun.

Enjoy,

Bedford

Thanks Bedford,
I want to go with gas too. The question with me now is which engine to go in for . Here are the options available to me :

A The Zenoah G38 is around 71 oz (engine + muffler) . http://www.horizonhobby.com/Products...ProdID=ZENE38A
B The SPE 40CC engine is just 53 ounce http://www.speengines.com/
C Also the RCGF 45CC is around 55 ounce. http://www.zrcgf.com/store/Results.cfm?category=2
D. a DL 50CC engine which is around 60 oz.

I have never really owned a gas airplane, and this would be my first. I seem to like Zenoah more than others, but not sure why they are soooo heavy.

Thanks for your help in selecting a powerplant for this kit !
-Gaurav

It's really easy to explain why the Zenoah engines are much heavier than the others which you are looking at.

The Zenoahs are basically industrial engines, from applications where weight in engine design was not a factor. However, being robust, with a maintenance free, long life is what counts there. So there's no problem using a magneto for ignition, building a large, sturdy, heavier crankcase, crankshaft or two ringed piston. Years ago, near the start of the gasoline/giant scale movement, they were adapted to model aircraft use, following the introduction of the Quadra back in the late 1970s which got the ball rolling.

The others do not use a magneto, have a much lighter, smaller crankcases, tend to use fewer bearings on the crankshafts and use one ring pistons instead of two ring pistons. Fewer parts. Less weight. However, once you add in all the other necessary stuff, such as ignition box, its requisite battery and optical kill switch, there is not a massive weight difference between the Zenoah engines and the others. Mind you. they are also less highly stressed since they do not put out as much power as the current designs. But then, they are also much likely to last much longer with less maintenance over their lives.

Have you ever actually checked the actual weights of any of these engines and accessories against the manufacturers' claimed specs? I have. And in most cases, the actual numbers were higher than those claimed. And in several cases, they were significantly higher. Paper claims mean very little. It's the actual numbers that count.

As for the DA50, that may be a bit too much engine for the plane. Basically, the fuselage is constructed of 1/8" lite ply. There is not any real aircraft grade ply in the plane. That includes the firewall.

I've got a Super Tigre 2500 in mine. And I can assure you, even with that, I've changed the nose and firewall construction to ensure that there are no surprises with construction or wood parts failure.

I put a 36cc Brillelli on mine. I can't remember offhand the weight of this engine, but I'm thinking it is about 3.5 pounds. It is a fine power plant for this model. Unfortunately, Brillelli is no longer in business.

My Decathlon weighs just a tiny bit under 19 pounds. The reason for that is two extra servos for the flaps I added. An extra servo for a tug release and an extra servo for a bomb bay/drop. There's 8 ounces right there. I did a Smart Fly power system... another 4 ounces. So, I hit the upper end of the weight range. I used a composite LG, which is not CF and is heavier than the stock aluminum. So, there's my extra weight.

Most of this was slightly rearward of the CoG. I wound up putting my ignition batteries up front and am in front of the most rearward CoG suggested in the manual.

BTW, I really like the flaps. Perhaps being on the heavy side is the reason for this, but when landing the model likes to drop when it slows. The flaps make a big difference with this. I'm still figuring out the model... maybe 10 flights now... but I've started using about 1/2 flaps for takeoff and it seems more docile there as well.

As for engines. 60 ounces sounds pretty heavy. I would stay light if I were you. The main consideration when selecting an engine is the cowling. It is not very wide. A Pitts style muffler is a really good idea. With the Brillelli I wound up with very little cutting. The carb is a side mount which angles down a bit (engine inverted) so the top of the cowling is uncut, only the carb hole in one side and I had very little cutting on the bottom... muffler and spark plug cap. I am extremely happy with the combo. I think I'd look at the RCGF first. I'm not super familiar with that engine, but it seems that they generally are not wide engines... maybe rear induction? You have about 6" to work with.

There is one thing that I wish I had done. I did not use the doubled firewall engine mount. The engine bolts conflicted with the secondary mount... it just wouldn't work for my install. I do wish I had tossed the firewall material (light ply) and used aircraft grade plywood. The light ply is pretty spongy. I've compressed the ply badly in order to finally have a secure engine mount. This of course weakens the ply. I just can't bring myself to replace it, but I might eventually need to plate the inside with a layer of good ply and the outside. The only issue here is the top engine t-nuts are no longer accessible. So, it's not a great situation. It would take some work to make the firewall during the build, as there are few notches and such, but I would most certainly consider something to make this stronger.

Other most important mods included making a slide out tray for the gas tank. Tygon gets stiff over time and must be replaced. Even if I did glow, there is just no way I would ever build a model where the tank couldn't be removed. I made a couple of little wooden rails and used 1/16" aircraft ply which slide into notches cut at the bottom of those rails.There is not much clearance for the 24oz Dubro tank, so you can't go very thick with whatever system you use.

I had my Decathlon at a Giant Fly In Saturday. It got a lot of attention. I made me feel particularly good with my build and colors. After all, this model looked pretty small out there as it was not far over the 80" wing minimum for flying. It was extremely windy.... 15 to 20 mph winds which were relentless all day. Pretty much everyone was not looking so good during landings. I hadn't flown this model in winds that high, so I had my fllying friend take it up as he is a much better pilot than myself. We first made a bomb run and dropped two dozen plastic Easter eggs on the runway in front of the stands. Got a nice applauds out of that. There were about 4 planes in the air at the time. The announcer described the different models for the crowd... Then I heard him pointing out one 3d bipe doing a pretty shaky KE. It was a day when such things were not easy due to the winds. So, I started giving my flying friend instruction... LOL!!! Me telling him what to do. Well, I knew the Decathlon could do it and I knew he could do it. So I told him to slow it down, roll it over into a knife edge. This put it into a very nice high alpha KE. Well, his skills kicked in from here. The runway there is 1000 feet long. He got it locked in, slow... about 20 feet above the runway... and did a most perfect straight and level KE for the whole distance and carried it out about another 500 feet past the end, where one has to pull out due to trees and buildings. We here all know of course that this IS and acrobatic trainer, but few in the crowd including the announcer knew that. There was amazement in his voice and another round of applauds.

Yes, the model is a really fun model. Mine really likes to be tossed about. It really likes rudder in turns... not just an average same 'ole flyer. It is making me a better pilot... forcing me to use all controls frequently during each flight. Simple aileron turns aren't very pretty unless you like to see the tail hanging down on turns... then again, I am still behind the central CoG setting, so this would be exaggerated a bit on my model. It does nice rolling circles... although I can't do that yet. Loop, rolls, rudder turns, inverted flight and KE are all in its arsenal. I'm looking forward to continuing with more flights, better figuring out how to fly the model and letting the 'acrobatic trainer' teach me how to do either new things... or do what I do with smaller models really well on a big model.

I'm really interested with the design of that tow hook you have behind the cockpit. Can you make a little sketch and also explain how it's mounted? My next project is a Dynaflite SD with Super Tiger 3250 for towing.

Dumorian. That looks like a solid spinner with a slot cut in it and probably has the servo controlled release rod coming up from the bottom. Is that a good towing position?

The tug release is a 'stud' bolt from an old 1978 Goldwing Vetter fairing. These were decorative addons. They were stainless steel and yes, that also look like a spinner! So, a bolt comes into the center from the bottom into a threaded area in the middle of the cone. The cone itself was hollow. I just cut through the side into the hollow area and then using a bit of brass tubing, made a channel for the control rod. I then filled the hollow area with epoxy. At this point I cut my slot again to get through the brass tubing and to clean out any extra epoxy. Then, I did some clean up and polishing around the edges with a file and sandpaper to make sure I wouldn't fray the tug line. There is a servo under this which simply moves the control rod up or down a bit... which is the release for the tug line. Basically, this was a look around in the 'what you have on hand' to make something. I really didn't think about it looking like a spinner until after it was done. It draws a fair amount of attention simply because it looks like a spinner.

As for the location of the release, this is as close to the suggested location as I could do on the Decathlon. The idea is to put it on top as close to or slightly rearward of the CoG. On real tugs, they are on the tail, but on models the glider can have total control over your tail... glider goes left, you turn right, glider goes up, you go down. Underneath... glider goes up.. you go down. On top... glider goes up all is good... glider goes down, you go up... still not so bad. The basic idea is the glider pilot is supposed to keep their model level and above you. As gliders generally climb faster than a plane, there is a normal tendency for them to rise off the ground and be above you. So mostly the glider pilot's job is to keep their glider level. You'll pull them in the direction you want them to go. The glider pilot of course should be prepared to keep the model slightly above you, as you do not want the tow cable to be pulling down on your tailfeathers... unless you have a very big engine capable of vertical while pulling a glider! Still this is just things going bad no matter what.

Both the glider and the tug should have a release. As soon as either pilot sees something going wrong, they should cut loose. Once it starts going wrong, it can go wrong in a hurry. Also, when bringing the tug back for a landing, in some situations you may need to be concerned about snagging the tow cable. These are normally about 100 to 120 feet long. Unless you have pristine field conditions... a huge landing area with no potential snags on the ground (tress, shrubs, fences, stobs, other aircraft, whatever), it's a best idea to do a fly by and drop the tug line and then come back around for the landing.

So, unfortunately I can't point you to where you might be able to find one of the 'studs' that I used for a tug release and the release position is a good one for the Decathlon. I have not done a tow with mine yet... Just did this from reading online and some tows with a Telemaster in the past.

Oh, thanks for the reply. I know what it is from your description. They do make solid spinner nuts that hold the pro on the engine that look just like that 'bullet', I have one! I"ve read where it should be positioned just aft of the CG which is not practical since it would be on top of the wing. I assume you beefed up the area pretty good.

My next project isthe Dynaflite with a Super Tiger 3250. I have the engine and a G38 as well but the ST is compact, lightand a wicked strong! I will run larger wheels and pants. I'm building it as a tow, so I'llbash scale a little bit. Thanks again.

For the tow mount, I ran a piece of pine crossways... perhaps 1" front to back by 3/4" tall. I fit it full length from side to side. I epoxied that into place. I then drilled through the fuse at each end and inserted a 1/4" dowel... which was then sanded down flush with the outside of the fuse. So, it's a pretty heavy pin from both ends and three sides are epoxied to the fuse. As the release is not very high above the fuse, I'm thinking almost all of the force is going to be to the rear, with not a lot of rotational force.

The Decathlon is a heavy model... and a lot of the weight is in the tail. You might want to move the tail servos up into the cockpit if you use the lighter engine. Try to keep it light when doing the tail feathers... and then before you go too far, try to get the engine hung onto the front and try to figure out your CoG.

The model is plenty strong for a gasser... aside from me thinking it needs a firewall upgrade for this... but it is solid and rugged. It would however be a shame to use that light engine and have to hang 6 or 8 ounces of lead up front.

Here is mine done with trim only window and balancing left to go.

Thanks Dumorian. I have also built full scale as well and when it comes to weight, the saying goes,"your building an airplane not a piano". I like the use of hardwood dowels and hardwood for the high load areas. I've read this whole thread, so I already know and have plans on lightening the tail and moving the servos up front. This is a terrific forum for the kit. I"ve done RC since the mid 60's and it's nice to see kit building still popular, building is like therapy.

I ordered the kit yesterday and willinitially only have limited time to devote to the build.
I'm most concerned about what model muffler will fit the ST 3250 and the cowl.
I don't enjoy cowl problems.

I am really happy with my Brillelli 36cc with the pitts muffler. Brillelli is no longer in business, so getting a new one isn't really an option. The good thing is it is a Poulan chainsaw motor, so parts won't be an issue. The carb is side mounted but angles downward... or to the top of the cylinder which is inverted. I did have to cut out the side for the carb, but it isn't a large cutout and makes activating the choke pretty easy. I did have to do just a bit on the bottom of the cowling so the plug cap would fit... but just the a tiny amount. It was as if this engine was made for this model... a very nice fit. Just a FYI entry here. I like gas. I'm not crazy about glow. I like to fly. I don't like to clean. But that's just me.

Man that thing looks great! I will have to do blue white and silver on my next project. It just turned out awesome! Let us know how the maiden goes. Best of luck!

Stevo,

Looking forward to your next project. Be sure to do a thread on it.

Rsad

Well I started the kit and got the tail feathers, built up formers, ribs and spars all done today. I'm ready to assemble the right wing panel.

But I'm stuck.

Obviously I'm missing something because I cannot figure outhow toput the washout in. They mention it's a 1/4 X 3/8 X 42 inch piece of balsa. I found that but where and how does this thing put in the washout??????

I can't see anywhere on the plans it is and the picture in the book was taken from across the street.

Anyone give me a clue?