Lifer

My Feedback: (1)

Very clear, and thank you for posting the pictures. Very ingenious.

karolh

Absolutely wonderful innovative thinking at work here ...... a really great fix.

lamarkeiko

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I just ordered a new RCGF 15cc BM from RCGF USA. I have a couple questions that I haven't found on this thread and would appreciate a little advice with.
To help with the advice, the engine is going on a Great Planes Revolver 70, which has a specs weight of 8.5 to 9.25 lb. I will be using the plane for pattern practice. Don't want speed, just power for vertical maneuvers.

I haven't ordered any props yet, so do any of you have a recommendation for prop size/manufacturer for my use?

The second question is the fuel tank size. The Revolver comes with a 14.2 oz fuel tank, which I think is way to large for this engine. I have a 4 Star 120 with a VVRC 20cc and 12oz tank installed that still has about 1/3 fuel left after 12 min. What size tank are you using, and how much time are you getting? I normally like to get about 12 minutes of air time, and have a little fuel to spare. I may have more questions later.

Thanks
Lamar

fby002

8 oz tank is plenty no recommendation on props, I would tend to go with the smallest recommended prop to start with.

karolh

A couple of my flying friends have this engine on their Hangar 9 Ultra Sticks 60 that are in the 7.0 - 8.0 lb. weight range and provides very good all around performance including quite good verticals on a 15x7 Xoar wood prop. I can't say how well it would do on say a 9.0 lb. model like your Revolver especially for pattern style aerobatics and quite possible might only be marginal in performance. However on a 10 oz tank this little engine will give 20 minutes of run time.

ahicks

My Feedback: (2)

Lamar, the "go to" gas engine for the Revolver is usually a 20cc. The DLE rear exhaust works pretty well because it's small foot print minimizing necessary hacking of the cowl. The 20 provide outstanding performance without being unusually heavy or presenting any trouble with balance.

I can't say that I've seen a 15cc mounted in a Revolver. Good vertical is not just about power, it's also weight. I would guess you'll need to be pretty careful there. Best of luck!

lamarkeiko

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Thanks guys
I have plenty of small tanks to convert to gas. I'll run the engine on a test stand first and I can get a fair idea on how long it will run with an 8 oz tank prior to installation. I'm thinking a larger lower pitch prop may be best for my needs. Maybe sticking to wood will help for keeping weight down.
I'm committed to to trying the RCGF 15cc engine for now. The specs on this engine rate it at 2.4 hp. The total weight with ignition and muffler is 27 oz. As a comparison specs, the OS ax 75 is also rated at 2.4 hp, and it weighs 26.46 oz with muffler. This engine is the top of the range 2 stroke recommended in the Revolver manual, so one would think the RCGF 15 would be ok. If it ends up I need more engine, the footprint is almost identical to the DLE 20, and should be an easy change out.
Lamar

Truckracer

My Feedback: (19)

Please report back how the engine works out for you. With these smaller engines getting more popular, we all need to increase our knowledge base.

karolh

Best of luck with your intended install and be sure to let us know how it turned out as we can learn from the experience of others.

karolh

Woooiiieee, Truckracer you beat me to it by mere inches

ahicks

My Feedback: (2)

Lamar, I don't know if you've seen it or not, but there's an incredible amount of 70 Revolver data in a string here on RCU, much of it devoted to gas conversions. LOTS of building notes. As a former huge fan of this plane (since moved on to 3D), I can guarantee the one you need to pay particular attention to is regarding the landing gear mount. That WILL fail if not reinforced, and it's much easier to reinforce while building, prior to it failing. It's not a difficult mod. The hardest part is realizing it does need to be done.

Last, please realize I do have an open mind. Projects like yours always sound interesting as I'm a big fan of the small gassers. Very curious how you make out as well. -Al

http://www.rcuniverse.com/forum/arf-...-revolver.html

lamarkeiko

My Feedback: (1)

Yes, I have been reading up a lot on the Revolver build threads. It seems like almost 100% failure with the landing gear with people that didn't reinforce the LG prior to flying. That is one item I will definitely be working on.
It will be some time before I'll be able to report back on the performance of the engine with the Revolver. I should be getting the engine by the end of the week, but weather will be the big factor holding me back from flying.
Lamar

lamarkeiko

My Feedback: (1)

I've come up with another question. I have a 2100 ma LiFe 6.6 volt battery that I will be using to power my receiver and 5 servos for the Revolver 70 that my RCGF 15cc engine will be used in. Can I also use that battery for the ignition? The RCGF ignition can use 4.8 to 8.4 vdc. I was thinking I could use a servo y lead from the battery to go to the receiver and ignition. I may not be seeing the full picture of why I shouldn't do this, so could anyone enlighten me. It just seems like a good way to not have to use another battery.

Lamar

Truckracer

My Feedback: (19)

Tech Aero IBEC

karolh

Ideally you should use a battery that has two power leads and one balance tap, so one power lead for the Rx and the other for the ignition rather than using a 'Y' connector on a single lead battery which could be asking for trouble. I use a one LiFe battery arrangement in my 20cc models with an RC exl electronic ignition kill switch and since your ignition is rated at 8.4 volts no need for a voltage regulator.

Lifer

My Feedback: (1)

What you ask is exactly what I have been doing for many years with no issues. I have used separate packs, IBEC's and single packs for ignition and receiver and all have worked flawlessly.

ahicks

My Feedback: (2)

Might be a good plan to ask some of these questions over in the "Larger Revolver" string linked above. They will be very keyed in on keeping things light and sturdy.
To answer your question, agree with the single battery plan, and the 2 outputs from it. From there things change. Here's a diagram drawn up by somebody here, illustrating an idea I've been pushing for a while now. It uses 2 switches for power redundancy, and as planes like this are often flown hard with some pretty powerful digital servos, the double output wire battery w/2 switches plan offers maximum potential amperage delivery to the receiver/flight pack. Pretty popular plan on 20-30cc hot rods.The "Y" is placed in the rudder circuit to provide it a straight shot to the battery (without going through the receiver) for the rudder during periods of high demand (like knife edge flight for instance). -Al

lamarkeiko

My Feedback: (1)

Choke & throttle setup



Revolver with RCGF 15 cc engine
It's been taking me a long time to get my Revolver and RCGF 15 engine ready for flying due to other commitments, but I think I'm there now and am anxious to try them out. My question is how much breaking in of the engine on the ground do I need before flying. At this time I have ran 4+ 10 oz tanks of fuel through the engine amounting to about 90 minutes of run time. I've done a little adjustment of the high speed needle, and the engine seems to idle and accelerate nice now. The manual mentions a couple gallons of fuel for break in. Would I be safe to fly now, and do the rest of the breaking in in the air?

Lamar

Lifer

My Feedback: (1)

Everybody has their own way to break in engines, but I usually set the needles a tad rich, and start flying. Listen to the engine in the air and adjust the needles accordingly. Simple, and a lot more fun than staring at a bench-mounted engine!

ahicks

My Feedback: (2)

As soon as you feel familiar with the engine, and feel it's running right, go for it.

karolh

As Al said, as soon as you feel comfortable go for it, plus 40 ozs. of fuel burning on these little gems is quite a bit of running so your engine should be ready to go. Must also commend you on your very neat and well thought out install. Looking forward to hearing about your successful maiden.

lamarkeiko

My Feedback: (1)

I did my maiden flight yesterday, and I wish I could report a successful flight, but that wasn't the case. I had a good takeoff, did some trimming on the elevator and ailerons and flew around for about 10 minutes and did some basic maneuvers like rolls and 1/2 reverse Cuban 8. The engine was running fairly rich and I wasn't getting full rpm. I was just about ready to bring it in, when the engine quit. Found out latter I ran out of fuel. I was up fairly high when the engine quit, and would normally have had plenty of time to bring it in with no problem, but due to me still being unfamilar with the plane I did the down wind turn to the runway much shorter than I should have. I was coming in nice and straight to the runway, but way too high. the plane was still about 10' high and moving fast as it crossed in front of me. It would have touched down probably off the runway end and rolled out into an area which was not so good. My initial reaction was to give it a quick down elevator then flair it out quickly to have some roll out. I had did my take off on low rates, but did most of my flying on high rates, which I was still on. When I bumped the down elevator the plane reacted much faster than expected, and before could level it out again it came in hard on the nose. Totally broke off the nose at the firewall.
I have had my share of rough landings, but I was a little surprised how easily the nose broke off. Closer examination of the plane afterwards, I could see the fuselage sides are only 1/16" thick with lots of holes to keep the plane light. It looks bad now, but I think it is repairable. No damage elsewhere to the plane except the spark plug broke off.
I totally misjudged the fuel run time, but that shouldn't have had any bearing on this mishap. Was planning on doing some practice approches prior to landing, but didn't get that chance.

Lamar

ahicks

My Feedback: (2)

Time flies when you're having fun! If you hit the spark plug hard enough to break it, you might just as well order out a spark plug boot so you'll have one when you go to get it running again. There's about a 80% chance the silicone liner inside tore when the plug broke. The engine will not start like that as the spark is guaranteed to leak to the metal boot through that tear.....

Truckracer

My Feedback: (19)

lamarkeiko

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Yes. The spark plug cap needs replacing. It is bent and the silicone insulation is torn. I've never replaced a cap before. Are there any instructions or special tools for the job?
I've already stripped the broken nose pieces down for gluing together. It will be stronger than original once I'm done.
Lamar