Found out just how tail heavy you can fly and still (JUST BARELY) land a 50cc Wild Hare Sukhoi today.......DO NOT want to do that again! Mr. Roboto65's Sukhoi lives...

OK we put 2 more flights on today with an ADJUSTED CG she fly's much better even in 17-18mph winds.

Greg so how far back from the leading edge (at the fuse side) was your cg on your first flight? Where are you now?

We didnt measure at the fuse sides, I can next time I put it together, ROBOTO65 had to head back south and left the bird at my place [>:] till he can pick it up later. SO I will get another opportunity to play with it before its gone hehehe.

WE used Tom's method of marking the wing tips with a string, and we were behind the aft mark approximately 1/2-5/8". To move the CG forward we installed a CF tube on the horizontals saving a wopping .6 oz's LoL, then extended the engine standoff another 1/4" (they are now 1 1/2" long), as well as added a 3 1/2" aluminum spinner. RX, regulator, battery, etc were as close to the wing tube as possible, with ignition components as far forward on the engine box as possible to include throttle servo in the engine box.

Current CG is about 80% of the tube to the aft and it feels nice! We had strong winds today so it threw alot of testing off. I could put in the wind pull to and idle (as if you were going to harrier) and with low rates (as manual suggests, 12° if memory serves me) the elevators were able to hold a harrier LoL. But most of that was the wind.

This Sukhoi came out at 16 lbs 15 oz's before we "revised" it with the spinner and such. Reason we attempted the maiden with the rearward CG is that I own the prototype to this bird from Tom, and I have its CG slightly aft of the wing tube and its slightly aft of neutral. I guess that extra 3/8" or so made all the difference hehehehe. Tom's birds are all so stable that you can really push the limits on the CG, I guess we found that limit! LoL.

Oh yeah SHE lives but she was handful with the CG back where it was like Greg said we moved the engine forward and Carbon Tailtube and very good but time will tell have to put some more time on her but was very comfortable with it the second day even with the high winds have video but very windy have to take the noise out heck Greg had a hard time holding the camera still!!! I am very pleased such a sweet bird !!!! Waiting on my graphics now LOL


Thanks Greg and TOM !

She gets right "pitchy" for landings with the CG too far aft. It's real easy to break props that way. Don't ask...

Oh I took off and almost right to a harrier LOL lots on down trim hehehe then came time to land Oh Greg had fun let me tell you three attemps and way rich on the low end we found out later a full turn LOL and he landed safe and sound!!!!

Hey Pat Roy, and C/F wing tubes!!!! dont ask
Lee

Hey guys just had the pleasure of running the first tank of fuel through my toc53. She made about 6600 on a 22x8 bunny just for a short burst. Transition from idle to wide open has a lag if I let it idle for awhile, seems to load up a bit. Is that something I should adjust after more run time. Seems the more it ran, the higher the idle got, had to keep lowering the trim after about half a tank it was stable, is this normal? Lots of shake at low idle more than I've seen with any of my other gassers but as soon as I came off idle it was pretty smooth anybody else see anything similar? All in all I think it ran good really strong on the top end nice midrange no fuel spitting out the carb. If I get the transition to smooth out it will be time to let this bird leave the nest wish me luck and thanks for all the help. MD

Well I would try leaning out the low end thats what we ran into. When I got my new 3MM also seems that they are refining things does anyone have more than one I have 2 and the muffler down pipe went from being about an 1" to about 5/8" seems they shrunk it a bit maybe for back pressure. But the low end was about a turn rich so we leaned her down and she runs great now!!!

Hey thanks thats what I'll do. How well do they hold idle any flame outs in spins or snaps?

No not at all keep the idle up for a while till she has a gallon or so thru her she will settle in I have not had any problem with dead sticks yet. I mean all engines are picky when new and this motor is no different..

Much of the shaking is due to being out of tune. 100% of the lag is as well. Every engine of every type has to be tuned to the location it's in, the prop that's being used, and the fuel/oil mix ratios.

Tune it has Pat says, and here is a quote from Pat as well.. Bring it to about 2500-3000 rpms or so with trim, lean peak the low needle, then check high. GO FLY!
There is no reason to set a gasoline engine with a rich needle setting to break it, you do that with oil percentage, such as 32:1 for x many tanks, and such. Running a gasser rich will only carbon up the engine and potentially foul the plug.

Speaking of engine setup. My toc53 is a standard setup. I have run 4 or 5 tanks of fuel thru it and it runs great. At WOT I am reading 6800 rpm, it has a great, stable idle and good throttle response. The only issue I have had is getting it started in the first place. I have the cowl removed so I can watch everything and notice that there is not as much fuel draw when choked as I anticipated. It takes a lot of flipping or holding my finger over the choke plate hole to get all the air out of the line. Once the line is fully "primed" everything is great. Has anyone else experienced this? Suggestions? Once the cowl is in place life gets tougher since it is hard to reach anything or see what is going on inside. And I try to be really careful being in front of such a large prop, so I dlo't like random flipping of the prop in case of a sudden unanticipated firing. I do empty the tank after each session so the line is empty each time I start the engine again.

I have found quite the opposite the 2 engines I have flood at the slightest.As a matter a fact MOST gas engines have the starting regimen of choke till pop and then turn choke off and then flip to start. Mine need choke but I do not wait till it pops no 3 or 4 flips take choke off and start!!!!

It was recommended to me to not empty the tank fully and you won't have the prime problem the next time....and it works

Bari1 I read that if you solder up the hole in the choke plate it will draw the fuel better it might help your situation. Thanks to all for your responses.

Thanks for all the responses. one of these days the snow will leave and I can try to fly! I had wondered about closing the choke plate hole, but didn't want to do if if not necessary. I will try the "not draining" first. I am so used to emptying my fuel tanks after a day of flying that I assumed it was still a good idea with gas.

I put silicone over the hole in the choke plate, you don't have to remove the plate to use the silicone.

Jeez mate what sort of silicone are you using, all the stuff I have used will not withstand petrol????
Lee

Lee,

Man you talk funny, "mate" "petrol", you need to come north a bit and learn real English. Just kidding, my wife and I enjoyed our two weeks in Australia. Sorry I can't exactly answer your question because the tube of silicone is up in Minnesota and I won't be back there until early May. I thought all silicones were impervious to gas. The stuff I've used is blue in color, and I believe it is advertised as a gasket material used in car engines. I hope this helps a little.

G'day
Chuck

Chuck
Ok buddy, I'll check up on the gas silicone. Hows that mate!!. Seriously would love to cross the pond and see your neck of the woods, hope to soon???
I think your right about the blue stuff, will check further. Just got my graphics form B&E graphics on your side of the pond. Flew my plane this weekend for the maiden, "unreal"
What more can I say will post some pics
Lee

G'Day Lee!

He speaks the Queen's English. Ours has been "de-tuned" rather savagely and turned into something that's mostly slang and abbreviations in common communications. You just have to visit his country!!! It's an absolutely wonderful place that brings awe to the eyes and culture to the mind everywhere you go. I just have to go back one of these days! Don't order Fosters when you visit a pub. They have some absolutely superb beers over there and Fosters is not one of them. Even their Guiness is much better than ours. Oh, the sheilas are gorgeous and in the back areas take rather kindly to a Yank accent.

Better not to close off the opening in the choke plate. An engine has to have some air to get started with, and closing it off causes easier flooding. I'd tighten up the screws on both carb cover plates and see if that helps. Perhaps check the carb bolts for tightness as well. Definately look for air leaks in the tank plumbing and lines to the carb. I had two of the 3MM's for test purposes and both drew fuel when choked quite well.

I've revised my idle tuning rpm down to a max of 2,000. 3,000 puts the engine a little too close to the transition point for the low to high needle change over.

look out for the rabbit
Lee