86" Yak and G62

[3D Meatshield]

Hey guys, I am finally the proud owner of an 86" Yak, and chose a G62 to power it. This being my first gasser build, I'm a bit confused as to mounting the zenoah. I see and understand what the 3W and DA cutout marks are for, but I'm not sure as to how much of that I'll need to open with respect to the G62. After standoffs, the only thing protruding through the firewall appears to be the shaft itself, so do I really need to open it up as much? And seeing as how I am overpowering some, should I go so far as to glass the backside of the engine box for reinforcement? Or is it substantial enough to handle the 62 as is? I'm a 3D noob right now, but I'm sure that once this plane is balanced right and flown enough to be comfortable with it, I'll fly it like I hate it, just like I do the rest of them I would hate to lose the front of the fuselage for doing extreme stuff with an overpowered plane.

I'm also looking for reccomendations on spinners and smoke mufflers. Spinners, I am clueless; for the muffler I am thinking a Bisson wraparound. I want to keep as much inside the cowl as possible- which, even with the 62, seems to be an easy task- the cowl on this thing is as big as a small wastebasket!


By the way- I just wanted to mention that when I unpacked this plane, I realized that there was not one single part of it that needed to be touched up with a heat gun or iron. It is essentially flawless. Proof indeed that you get what you pay for. Kudo's to QQAC.

[2walla]

If you are bent on using the 62, see if Ralph Cunningham is still working them over, if he isn't , buy a lightweight 50. Nothing wrong with a 62 but if you want to learn to 3d the 2-3 lb weight penalty of a g62 is hard to overcome on a 86" airframe.

[3D Meatshield]

Anyone else?

I already have the engine so it's pretty much set in stone that I'll be powering it with the 62. Can't afford a DA with everything else I still need to get, so it's really my only option. Has anyone done this setup before? I'd appreciate your insight and advice before I start tearing into it and make a whoops.

[davensocal]

I did a G62 in a Cap-232, and it was a mistake.. That big magneto engine is too heavy, and produces power at the wrong rpms.. If at all possible, get a DA.. There is a reason they are so expensive, they perform extremely well, have a high resale, and have unbeatable service. Used with exh can be had for around $500..

OK, now that that is done :-)

I would recommend getting an ignition for the G62, that will reduce the weight in the front.. Overall weight is the same, but you can shuffle it around a bit to help the CG.. I was going to put a CH ignition on it, but decided to sell the setup and get a used DA-50 setup instead (really glad I did!)
http://www.ch-ignitions.com/ Look for item #131

Don't bother with a spinner, you already have too much weight up front. If you can afford a 4" CF spinner, you can afford to ditch the G62 and get a DA. You could also get a DL, which I understand is much closer to the DA in weight and power, for about $350.

My 85" needs the batts as far forward as I can to balance her with a DA-50, so you might be alright.. Also, don't even think about a spring starter.. I think they are actually harder to start with a spring vs flipping the prop.

My G62 was using the Slimline wraparound pitts with smoke. This pipe includes a very nice preheater built in.. I used a Sullivan sky writer and MDW smoke oil.. I actually had a hard time with reducing the smoke fluid flow to avoid overwhelming the engine/pipe combo. I was running about 14% on the pump at full throttle, and 0% at 30% throttle. I am the only one smoking at this field, but I though the smoke was good.. In a tail slide I could almost loose sight of the plane, orientation definitely became difficult. I also mounted all of my smoke gear onto one plate, that I could remove from the aircraft when not in use.. All that smoke stuff adds a lot of extra weight.. Fun for showing off, sucks for flying though.
http://www.slimlineproducts.com/onli...iant_scale.htm

I would also recommend following the tuning guidelines at http://tech.flygsw.org/walbro_tuneup.htm

The only exception is that when you are done tuning, you probably just finished leaning out the bottom end several times. I would go back and tune the top end a little rich of highest RPM...

Sory, I can't help with mounting the G62 to the QQ.. Best I can offer is to set the plane standing on end (balanced with landing gear through steps of a ladder works). Then, place the engine without exh or prop onto the mount. Now play with the cowl to try and find the right location. The engine is held in place with it's own weight. When down, you can probably outline the standoffs as a reference point.

I am not an expert on Giant Scale, so this is a stretch.. I wouldn't glass the box, I would pin it. I is lighter and offers better strength on the joints. I think the plywood will handle it just fine.. I think you will have more issues with the weight of the G62, as opposed to the power.

[Sukhoikid]

	Quote: Originally Posted by 3D Meatshield
	Anyone else? I already have the engine so it's pretty much set in stone that I'll be powering it with the 62. Can't afford a DA with everything else I still need to get, so it's really my only option. Has anyone done this setup before? I'd appreciate your insight and advice before I start tearing into it and make a whoops.

Isnt the DL50 cheaper than the g62???

[3D Meatshield]

Well, Ralph is out of town right now so I won't know if he'll be able to do what needs done until he gets back home and has a chance to review what I need- and I really don't see him being able to pull it off. Nothing against Ralph, I just think I need too much and it just can't happen. To make the G62 fit will require substantial modifications, and after doing the math I am just about to the point of realizing that I screwed up by picking the 62 as a powerplant. I wasn't so concerned about the weight, using the logic that more power would offset the additional weight of the engine. I didn't bother to check dimensions beforehand and see just how large the 62 really is, and even if I used the shortest standoffs I could get, it is still too long of an engine to fit inside the cowl properly, let alone how far the shaft hub would protrude. Kind of an expensive lesson to learn in my first foray into giant scale but hey, if my dealer won't take the engine back in swap, I have a reason to buy an AT-6 now. Yeah I guess it ain't so set in stone, I think it was just dried clay :P

Dave- thanks for the info. Great post and really got me thinking. Unfortunately the DA is going to be out of the question if I want to fly this plane before the snow flies (unless I can talk the guy at aero tech into swapping my g62 for a DA), so I may have to get the DL. Of course, no one has a used DA available right now either, go figure.

In order to mount the 62 and keep it in the cowl, not only would I have to use the shortest standoffs possible, I would need the shaft and hub shortened, and also shorten the engine box as well- and the way this box is built I don't even want to think about tearing it apart.

Kevin- yeah, marginally cheaper. 20-25 bucks. It's a case of hindsight being 20/20, you know?

Thanks for the replies guys. This has been an eye-opener. Never knew going big would be as much of a pain in the ass as it is a wallet leech

[3D Meatshield]

Well, one problem solved.



The guys at the shop were cool enough to take my G62 back in swap for the only DA 50-R they had. Cost me money that I didn't really have to spend, but what the hell, you can't take it with ya right? Standoffs (it came with 2 1/2's and I need 1 1/4's) and a pipe are all I need now, and it won't cause me any undue butchery of the plane.

Question: QQ recommends an MTW 75 canister. From what I've been able to find, it doesn't appear to be a smoker. Can it be converted, or would I be better served getting a Bisson/Slimline/etc Pitt's style muffler for smoke? OR...... should I just forgo the smoke for now?

[davensocal]

Congrats! I think you will be much happier with the DA.. It is a sweet engine! I imagine you can see the difference just holding it in your hand, the milling of the case, how it was shortened to save weight.. Also, the DA is a reed valve engine, that and the ignition help alot!

OK, for your questions, I have to stretch a little..

My understanding is that the cans will give you better power, and smoother delivery across the whole RPM range..

However, I am flying the 85"QQ on a slimline pipe, and I have no issues at all.. I think a properly tuned engine with almost any pipe you will find for the DA (I don't think there is any junk pipes out there for that engine) should be sufficient for 70% of the people.

I am just starting 3D and IMAC, so maybe my tastes will change later.. However, I had an expert (A real expert that is currently placing high in IMAC competitions) fly my plane, and he gave it a big thumbs up. That tells me that I don't know how to fly, but my equipment is good.

So anyway, I would vote no on the cans.. You can always add them later. You have a budget, and the cans are going to stretch it even further.

I would recommend skipping the smoke for now, and just fly for a little while.. I would get the smoke pipe, and nothing else. You can add the rest later, and maybe even shop around for a while to get a good used pump.. As mentioned before, I was very happy with my slimline pitts with smoke. It is a very nice pipe, with excellent construction.

Good luck, and let us know how it shakes out..

[3D Meatshield]

	Quote: Originally Posted by davensocal
	I am just starting 3D and IMAC, so maybe my tastes will change later.. However, I had an expert (A real expert that is currently placing high in IMAC competitions) fly my plane, and he gave it a big thumbs up. That tells me that I don't know how to fly, but my equipment is good.

That's great! I had to chuckle when I read that, because I feel the same way about myself. Granted I'm not flying the Yak yet, but when I go out and give my UCD the business, spectators are always in awe just because of how easily it flips and rolls , and my hovers and harriers look cool to them- but I know they should look a LOT better. I don't know how to fly either, but at least I'm getting gear that will allow me to be good when my thumbs and brain are properly trained.

I'm just now starting to look into IMAC myself, and with any luck I'll find some local clubs that have competitions. I'd love to get in some Basic this year but it depends on how soon I get the Yak done. The UCD couples so bad I wouldn't even want to try.

Glad to hear the slimline is a good setup. My only concern was chopping up the cowl to fit it, because if I ever did go to a pipe then I'd need to get a new cowl- and 70 bucks for a painted fiberglass wastebasket... are you using the 2123 slimline on your yak? And would you mind taking a few pics showing how it fits, at least exiting the cowl?

Oh and as for the DA- what a piece of work that thing is. Such an excellent design in a compact package. I can't believe the difference between this and the G62. The 50 is compact enough that I had visions of shoehorning it into my UCD just for the hell of it Haha.

[davensocal]

Here are a couple of shots.. I got the plane used, and this is how it was setup.. Overall, I think it is about the best trim you could expect, I can just barely flex the cowl enough to get it off..

Sorry, I don't know the exact model number of the Slimline pipe I have. As far as I know, they don't mark the individual pipes.. It should be the 2123 though..

For the cowl replacement, how about a different perspective.. Learning 3D and IMAC, what are the chances you are going to trash the cowl before you outgrow the DA-50 with a somewhat stock exhaust?

I am trying to not see dollar signs whenever I see my plane close to the ground.. I am trying to give up, and accept the fact that I will stuff it into the ground, probably sooner than later.. I will feel a lot better when the pucker factor is diminished a little bit..

For sticking the DA into the UCD, I guess it depends on how hard the Yak assembly will be.. I bought mine on the advice of the guy who was selling it, but he was directing me away from more expensive aircraft he was selling, so he had no motive to lie. I am totally amazed at how easy the QQ Yak is to fly.. I have no interest in assembling any of my other planes, I have no interest in flying any other planes !

If you have a chance, check out the article on TBM about "how to be an awesome pilot".. Interesting and funny reading... Although I enjoy practicing spins and split cubans, I need to continue to fly knife edge and work on my rudder control and orientation..
http://troybuiltmodels.com/newsite/awesomepilot.html

Anyway, hope the pics help.. Remember mine is the 85", but it should be very close to the same dimensions.

[zoomer260]

Damn, I was all interested in this thread. Now it's just another QQ with a DA. Yawn.

Nah, congrats man ! Know you're gonna like it.

[3D Meatshield]

	Quote: Originally Posted by zoomer260
	Damn, I was all interested in this thread. Now it's just another QQ with a DA. Yawn. Nah, congrats man ! Know your gonna like it.

I can't deny, that was one of the reasons I started this project with the G62 in mind. Plus I'm a poor bastard, and 400-odd dollars is still 400 bucks. But I ended up spending it anyhow, because it was better than trying to re-engineer the engine box to fit the Zenoah while running the risk of completely ****ing it up.

Dave- thanks for the pics, that's exactly what I wanted to see. I'm wondering though- how much of the pipes were cut off to facilitate cowl removal? I've seen other planes that have chopped off an inch or so of the pipes to clear the cowl, and then I've seen others where the pipes were left intact and the cowl cutout was elongated so the cowl could slide over.

As far as replacing the cowl, I meant it in the sense that should I someday put the pipe on it, I would rather have the cleaner cowl without the big cutout where the pitts once was. I'm not concerned about trashing it on impact- my record has been that a swift meeting with the dirt usually entailed complete airframe replacement, and not just the cowl I don't even think about crashing when I'm flying. If it's gonna happen, it's gonna happen, and worrying about it while in the air would just divert my attention from practicing.

And as far as putting the DA in the Do- lol it's just a 60-sized Do, not the giant, and the DA mount is (from casual observation) too wide to fit on it. I'm not sure it would have the ground clearance to swing a 22 either. I just made that comment because I've developed the habit of overpowering my planes, and how wild would it be to have a 50cc on the front of a 60-size Hell, the saito 125 I have on my Do already broke the firewall once, the DA would likely fly off on its own with the firewall and leave the rest of the plane sitting in the grass

And thanks for the link!

[zoomer260]

I have a Yak with a DL-50 on the nose now. Should I build/aquire another 50cc it will get my G-62 that's bored to death. Assuming the Yak is still in one piece !

After a trip to Ralph the weight penalty is only about a pound. BUT, I already have the G-62. It's an oldie but goldie !

[davensocal]

3D-
My pipes are original length.. It is a very snug fit, and you have to deform the cowl a little bit to get it on/off... The top of the cowl has to clear the prop shaft and kind of rotate down to be removed. To do this, you have to press the sides in a little to make a taco and get another 1/2" of clearance at the top.

However, something to think about.. If I lose my landing gear in a rough landing, chances are good I will take the motor box as well as the weight of the plane will fall onto the pipes. Some of the guys at my field cut the pipes to be even with the bottom of the fuse, and then add a little bit of rubber tube to bring them back to original length.. Doing something like this would help with the cutout as you could put the extensions on after the cowl is in place, and the short pipes protect the motor box..

I thought about doing this, but it runs great the way it is, so I am not going to mess with it. I need to quit tweaking and just fly.

[3D Meatshield]

Heh, as much as I dreaded the idea of carving the engine box apart to mount the G62, I think I'll be trimming the pipes. I seem to be rather adept at removing the gear from new planes and I would rather repair the bottom of the fuse than try to rebuild the engine box.

Zoomer- putting that zenoah on the Yak would be quite the engineering feat, even after Ralph worked his magic. I emailed him to work on the G62 before I swapped it for the DA, but he was out of town and I told him not to bother til he got back. Nevertheless it would have required him to shorten his mount where he puts the ignition, shorten the shaft and shorten the prop hub- all total about 2 1/2 inches. I don't know how good he is, but just looking at the 62 I would guess that no one is that good. The cowl on the yak is long, but there is only 3 1/2" of room from the face of the firewall to the inner face of the cowl. Just not enough room to hide that zenoah. However, if you are skilled at chopping balsa and liteply, then you'd have a hell of a chance pulling it off.

I wanna see it when you do