RCGF Updates

RCGF updated their website! Sweet look. By the way, saw they are selling the 15cc Beam Mount side muffler engine for $209, the rear muffler for $199. That's the same price as the 10cc. And a 30cc TWIN is coming. Check it out!

I have had great luck with these engines, except for the 10cc on the Stik. I think it's a bad carb... The need to re-tune it every time I start it suggests this, and the curious way it runs at times, like there is a fuel flow issue. Joe Nelson thinks its the carb too. I finally decided to change it. I went to the RCGF website yesterday and it must have been while they were updating it as the website URL could not be found. Gave me a fright that it folded! Nope, as noted, new site. But since they were closed at the time, I went looking for what to buy. As I looked at Google pickings there was a discussion on RC Universe about carbs on these RCGF and similar engines being too big, like 2-4 times too big, and that this made them run  inefficiently, rich.

** RCGF-USA uses only Walbro carbs now.**

"I would offer that the carb that comes on the 10cc rear exhaust engine is a Walbro clone with a 10mm or so venturi, that is 3-4 times the size it needs to be. To get good throttle response requires a super rich low speed mixture. After many hours messing around trying to civilize this engine, it was discovered that if you slowed the throttle opening using the same process you would on wing flaps or gear doors, allowed for a dramatically leaner low speed mixture.

Those with automotive hot rod experience might relate to a comparison of having a 1050 Holley carb on a 302 small block, using mechanical secondaries. When the carb is opened quickly there is a complete loss of vacuum causing the engine to fall flat on it's face. In the caes of the 10cc RCGF, slowing the carb opening allows the engine to maintain vacuum, resulting in a much more desirable acceleration.

Worth noting is the slow carb opening is not noticeable in use, and the engine handles nicely, much like bigger rear carb engines, and flip starts easily."  ~ AHICKS

Going smaller might lead to loss of WOT RPM, but better and more linear power. The stock carb is 10mm, and the discussion was bringing that down to 7.1mm using a Walbro WA-80 carb. Well, I could not find one... I even wrote Walbro (they are not making them anymore but are thinking about it... and would need a run of 40 before they reopened the line; email with Walbro). The WA-80 supposedly is a perfect retrofit for the stock Chinese one (which, by the way works just fine on the Sukhoi RCGF 10cc). So I bought one of the only two available new, on eBay for $35.

While I do like the Evolution 10cc, I still have lost my heart to these RCGF engines. Hopefully this solves this problem with the Stik's RCGF 10cc. I haven't tried running it since the other day when I finally got her re-tuned again. Her high idle shouldn't still be an issue... We'll see.

The other suggestion I have seen for these really small engines is brought up again by AHICKS:

"Worthy of note, when installing the Walbro carb, many advise the use of some sort of thermal break between the engine and carb. I laminated about 1/4" if fiberglass scraps together with some CA and carved one out from that. A stack of gaskets may work as well, or, see what happens without!"  ~AHICKS

I don't have any materials that I know of to make this thermal break, so will try it without it... Not sure this is a thing?

SCUTTLEBUTT:  Well this is interesting...  VVRC used to be a drop shipper for RCGF-USA (You order from VVRC, but the product is sent from RCGF-USA). RCGF-USA makes these engines in China, but the company is US owned. There were issues with the molds they used in the early years. RCGF-USA developed their own molds for these engines and have solved the QA issues, and now produce great engines at great prices. More importantly, they have always offered personal, outstanding customer service. You talk to the owner, not an employee. I have used VVRC in the past and am disappointed in their aggressive and inflammatory posting. I don't know where Tom is getting his RCGF engines, but if they are from those old molds, buyer beware... I would not buy any RCGF product from anyone but RCGF-USA.

Tune Up Day for the Stik's RCGF 10cc

Last time I flew the Stik she had some challenges getting and staying tuned. The QuikFire Filter is nice, but I am not sure they offer an advantage. I like the filter system on it much better than a screen, but honestly I don't know its any better than a simple screen filter. Certainly its costlier. I don't know that I will include them in my next build. This one leaked, so I replaced it with a simple 3-way screen filter. The engine runs so much better.

I simplified the fuel system.  Kept the QuikFire clamp and used it to hold the 

screen 3-way filter in place. This cleaner approach to the engine from the fuel tank

made for a much smoother running engine, in particular with shifting

fuel demands in aggressive throttle management.

The RCGF 10cc engine continues to be a bit of an enigma. I still love them, and don't think there is a better, more affordable 10cc engine. But I have to admit I have no idea which way to turn the low needle... Conventionally you tune the high end for max RPM, and that needle is easy. Then you tune the low end for smooth fast full throttle. One would think that if it bogs down, you richen it, turn it out. The idea being that it needs more flow. You find the leanest point that gives you a smooth, non-bogging transition. Tuning the low needle is a constant challenge on this engine. The other traditional bit is that once you get a gas engine tuned, that's pretty much it for the season. One of the reasons I like my Stik is the open engine bay: no cowl to take on and off, because it seems I am constantly having to re-tune the low needle.  I haven't flow the 26cc much, as I finished the Waco last fall just as the winter closed the flying season, but in the short time it seemed much more stable. The fact is, though, that I am breaking in a new cylinder on the Stik's 10cc, so it is expected to be a bit wonky.

Running the 10cc idle to full, half to full, back to idle, after the tuning. Max RPM and smoothest I could get the transitions. Too lean on the low needle and she would quit sometimes in idle, especially dropping from full throttle. Kept having to shift the low endpoint on the transmitter to find a good balance that gave me a reasonably low idle without stalling the motor on full throttle and on idle back. She seems to be running pretty smooth. I will be in Londonderry tomorrow for an appointment, so will pack up a couple planes to fly off the mountain top in Hudson at SNHRCC. We'll see how she does.

Looks like the gang at Misfits in Auburn have accepted my membership! The field is closed due to mud on the road in and the parking area. Once it dries I will be doing more flying out there. But for the need to have a buddy, the geotex is awesome, and the open space makes for better flying. I love the gang and the geotex out at Flying Eagles in Merrimack, but just hate flying in and out of "The Hole" of the trees that surround the field.

I am charging the packs on the Stik and the Sukhoi 10cc's, and some 3S 2200's for the HobbyKing foam Sbach to fly tomorrow. The winds at The Mountain are always a bit more brisk than the prevailing winds, so it may be a bust when I get there, but we'll see.

Hangar 9 Ultra Stick 10cc ARF Build Begins

 

Sold my Dx8 Gen 1 and used the proceeds towards finally buying the Hangar 9 Ultra Stick 10cc from my LHS, ABC Hobbies in Windham. I wanted an Ultra Stick for years, but they went discontinued. I ended up with an Ugky Stick, and I loved it! I planted it after many years of great flying, and in the interim, the new and improved Ultra Stick came out. For its simplicity its a bit pricey, but its worth it! Since the 60" wing comes in one piece, the box is over 60"long. I had to use panoramic view to get it all in!

Ginormous wing. Top side.

Underside.

For a few minutes I thought about using the stock CA hinges, but they always come loose. I wasn't sure I was in the mood for installing Du-Bro Nylon hinges, but I prefer them.

So, that's what I did.

One of the things I don't love about them is that they take so many steps, others are keeping epoxy out of the hinge, and if one of them goes slightly off angle the surface moves stiffly. I line them up dry fitting both side and mark the centers, use my Du-Bro hinge cutting tools to make the wider space required for the nylon hinges, great the hinge lightly to keep epoxy out, then using 30 min epoxy set them kne surface at a time.

Everything looske lined up! Only one hing went slightly askew, on the right flap. It works fine, however. The only reason that happened is the epoxy was curing faster than expected...

The Ugly Stick had a nice Tru-Turn bullet spinner on it, but this airframe is more slick and sporty, so I went with a 2.25 inch aluminum cone spinner from Amazon. I am using the well running Evolution 10cc gas engine. I tried to find a Pitt style muffler from Evolution as it would be affordable, but there are none left for the 10cc. Horizon Hobby, for some reason, discontinued the Evolution gas engines. I don't think they even make nitros anymore.  I would very much prefer one... but it won't be cheap.

I like that the servo trays are already built. There is no skill to it, its just busy work, so having it already done is fine by me.

The ailerons and flaps are on a Y. You have to be careful with these setups, as was seen on the Spitfire, to get the servos facing the correct way to allow oposite aileron movement, and identical flap movement.

Wing is done!

Close up of the aileron and flap Ys.

I did this over a couple of days. I am looking forward to getting to the fuse next!

Sukhoi 10cc Back in Flight Ready Status

The other day I once again peeled the landing gear off the Sukhoi 10cc. This airframe has been with me for 4 years now, and her only issue has been her weak knees. I have always held to the practice that it's better the landing gear than the entire bottom of the plane, but I have had nothing but trouble keeping the gear on at all. Since I am quite willing to go back to the 10cc Sukhoi with the red Honda livery, I decided to build this baby up like a fortress. If she crashes the only thing left standing will the the frickin' landing gear!

So a landing in a head wind, a foot off the ground, wind stops, plane drops, should be no problem, but here we are.

And ate a bit of dirt... You can see the gear cleanly came off.

There really wasn't more than a middle block of wood left as the front attachment. This and some epoxy is all that held the front end of the gear in.  The screws were not strong, just RTL Fastener Servo Screws. She tore clean off as designed, just should not have.

This plank of wood on the right is tucked under each side of the fuse, so it's buttressed well. Covered the entire thing with epoxy. The left piece bears no stress as the back of the hardpoint has tabs into the back wall of the landing gear box.

Installed two beams of wood to fortify the fuse and the back of the landing gear box. These are wrapped in epoxy, and the upper piece (closest to the bottom of the fuse) is buttressed under the sides of the fuse.

The gear hardpoint with T-nuts, epoxied in place with 30 min epoxy. The left end (aft) has two large tabs that are in the buttressed and fortified back wall of the box. Put a piece of wood at the near end of the box to fortify this end, the other has one.

Put two long countersunk wood screws straight down into the base. Didn't want to weaken the hardpoint with the countersink, but had to for obvious reasons. This anchors the hardpoint to the piece of wood that is buttressed into the fuse. This is now very damn solid.

Further insurance. I put another long wood screw through the center of the landing gear through the hardpoint into the box. And if that's not enough, I threw two more through a piece of wood that is CA'd to the front wall and the landing gear, angled into the front wall of the box. Like I said, this will be the only part left in a crash. I didn't try to get it perfectly centered...

Painted with gloss black to make it a little less ugly.

Took a moment to install the 14 oz (414cc) Du-Bro tank. It had an 8 oz (255cc) tank. She will fly all day...

The previous post is about my surprise to find a black rubber stopper in the old tank. I usually spend more for the gas stopper I think they should just include. The old tank was splitting at the stopper so it was leaking, but the stopper itself is in perfect condition. I decided to use the new black one that came with the tank.

The Sukhoi 10cc is flight ready!

Evolution 10cc DISCONTINUED

Working on the Evo 10cc, snugged up the exhaust extensions which were leaking a bit, and wanted to snug up the carb screws. I snapped off the fuel nipple trying to tighten it. That's when I learned Horzion Hobby has discontinued the engine and that the nipples are NIS. Crap. Found some at GravesRC, got two, for about $6, but shipping cost $8. Damn. I could not get the retaining bolt off the engine case to remove the carb, it stripped its cap. So I had to grind a line for a slot screwdrived and got that off. Turns out the screw is an odd size M2.5 16mm. So I had to order some from RTL Fastners. Jeez.

I did see that the guide screw for the barrel throttle wasn't quite right so the throttle did not close. I greased it and adjusted it, now it has full smooth range of motion. Broke out the manual and set the screws back to stock settings, High is 2.5 turns, Low is a whoppjng 4.25 turns. Once I get the fuel nipple and the 2.5mm clamp screw in, I can put it back, redo the fuel lines (there is a leak somewhere, maybe it was the carb).

So HH has discontinued the 10cc. Huh...

UPDATE 10/16/19: One of the reasons I really love Horizon Hobby is their incredbile customer service. Yesterday I left a note asking about HH having d/c'd the 10cc Evo and my being at a loss for a fuel nipple. Dave Poole the Service Manager has one laying around and will have it sent to me gratis. I love these guys!

Test Stand and RCGF-USA 10cc Survived

I had removed the RCGF-USA 10cc from the Stik that took a massively destructive header right on to the engine. Before I committed it to the new Spitfire, I wanted to make sure that it survived intact. All tree blades were snapped at the hub and she came down right on the hub, which is ground up quite a bit.

The RCGF-USA 10cc on the newly built test stand.

Runs perfect!

A simple rig. Manual throttle, the ignition  is fro  the engine and will be installed on the Spitfire. On old NiMH battery pack and the tachometer are also fixed to the rig. I put the 10 cc mount on one side so I can put a larger engine ,out on the other side if ever needed. 

The RCGF-USA 10cc on the test stand. Brief cut.

Faith Restored: Evolution 10cc runs perfectly!

Back in June I pancaked the Sbach and her Evolution 10cc when I lost control authority. I thought this was a radio issue (don't we always?) but knowing the radio is fine having had it inspected by Horizon Hobby/Spektrum, I have to think I just stalled it... Anywho's, I, of course, haven't run the engine since. Today I put her on the test bed.

It's narrower than the RCGF-USA 10cc the mounts are set up for. To keep it simple I just made a thingy. Two bolts on the left, on on the right.

Didn't take much to get her started once I got fuel to the spark.

Happens. I was finger choking the carb (has no choke) and touched the sparky, giving me a little surprise shock, making me jump and nicking my finger in the back of the prop.

UPDATE 9/20/20: This is what it looks like this morning when I took the band-aid off. It looks much better a few hours later when I let it dry out a bit. It's really not as bad as it looks.

I don't think I have ever had an engine exceed 9500 RPM before! 

The Evolution was rocking 10,250 at one point swinging a 13x6!

Listen to that sound!

Needless to say, my faith in the little Evolution is renewed, and as soon as they are back in stock its going on the Hangar 9 10cc Ultra Stick!

Soft RCGF (Original) Threads...

One of the few problems with the original version RCGF 10cc engine is the soft threading of the spark plug site at the top of the cylinder  (this engine is now "obsolete", and this is not a problem with RCGF-USA 10cc Stinger engines).  As of today I have stripped 3 of these in 9 years. Today was removing a spark plug wire from one of the oldest engines I have, probably 9 yrs old now, and the whole sparky came out still attached to the ignition plug adapter, stripped clean from the cylinder! 

All excited, the replacement muffler arrived from Joe Nelson at RCGF-USA! 

A little JB Weld gasketing and done!

Engine looks good, finished trim of the cowl for a nice fit (not shown).

All ready for testing. I noticed some fraying of the shrink wrap around the plug adapter so turned her over and pulled the plug. Resisted a bit then came out. ALL of it, sparky and all!

Clean stripped the cylinder head spark plug opening! The past two times I did this I "over tightened" the plug, so I've learned to have a soft touch.

Tried to re--tap it...

But there just wasn't enough left...

Just a peak at the inside holding the plug in, for giggles. I had wiped some of the carbon build up out, will give it a nice clean with some steel wool. I need a fix, surely this might happen again with the old cylinder heads.

So, instead of buying another cylinder head for $56, I decided to try this nifty adapter thingy! This is a 10mm-to-1/4 32 spark plug adapter from CH Ignitions, made of steel. I found myself thinking once again if anyone had a fix for this sort of thing. Surely this is not a unique problem. I hadn't searched for the right thing in the past, but today wondered if there was an adapter, and voila! So that's on its way, through eBay. Challenges remain: I have a 1.5 and a 1.75 modulus 10mm tap, not sure which this is, but have an inquiry in. Now this is really designed for a 10mm opening to allow a smaller spark, like down from a CM6 to a 1/4-32, not so much a retapped hole, so we'll see.

I will be pulling this motor and setting it aside. Joe has sent me a replacement engine for the Stik's RCGF 10cc, also about 9 years old. I did a number on it and he called it "kaput". Once that's in we can get this engine tested and get her up in the air! Hopefully that will be here in the next few days!

Ultra Stick 10cc Flight Ready and Aileron Fixed!

 The other day I dusted off the EVO 10cc Ultra Stick and fixed a few gripes.  Today I finished and she is flight ready.

Last year the Ugly Stick died a fantastic death when the un-commanded aileron flutter caught up with me a year ago last June. I put the same electronics into the Ultra Stick, and the flutter was still there. So I exchanged the servos in the ailerons, and put a capacitor on the receiver to clean up and stabilize the power (see that last link). Today I finally put the wing back on and in the process of tuning the engine, noted the flutter is gone. G-O-N-E, gone.

Finally, a nice idle that is a little unstable, but not quitting, 

very nice high end RPM output, and no aileron flutter!

I love this plane. I hope her performance doesn't disappoint.

Evolution 10cc. Not a big fan of the carb.

Weighs in at 9-1/2 lbs, consistent with the weight last fall. She is "designed" for 7 lbs, I wonder if that's her electric weight? Her dry CG is spot on.

But it took a pound of lead (473gms) as one momma block under that white piece of foam, up against the forward bulkhead. It took almost as much if I used smaller weights packed in more forward, around the fuel tank. Opted to just keep the honker in place.

Tomorrow, weather permitting, we fly!