tripower222

My Feedback: (5)

Ok here is the scoop,</p>

I have been out of model flying for 18 years and wanted to get back in. About a month ago I bought a 1/4 scale Sig Cub 105" wing span (not clip wing) on ebay. the plane has a converted weed wacker engine on it that seemed to run ok befor flight. I purchased and built a set of Sig 1/4 scale floats for it and gave it a try.

All worked out great except !!!! DANG!!!! she is way under powered, almost couldn't get off the water and once it did super slow climb.</p>


Info:
The plane weighs 18 lbs 2oz. ready to fly with half tank of fuel (14lb. 8oz. plane, 3lb. 10oz. floats)
The engine turned a 16x6 prop 6700 rpm static and a 16x8 prop 6600 rpm I used th 16x8 for the flight.</p>

Now as for choosing the motor I looked at the Zenoah G26, the Fuji Imvac BT24 and the CRRC 26cc weight is really of no concern as the plane is balanced well and they are all lighter than the current engine an would likely need to add the weight back for balancing anyway
Obviously power is my main concern. I don&rsquo;t see a HP rating on the Zenoah nor would I put much faith is manufacture HP comparisons from one MFG to another. I was looking for experience to help with that.</p>

Also electronic ignition or not?</p>

Let me say that the difference in cost on all these engines is not a big deal to me I just want to get it right.
It seems there is really no weight advantage by my calculations (if it mattered in my situation) by the time you put the ignition module, battery, and wiring in place of the magneto it&rsquo;s a wash and certainly less dependable (with the hassles of keeping the battery charged). My question to the experienced is, is there really a difference performance either power, smoothness, or idle that would make it worth it?
</p>

Woody218

My Feedback: (24)

An engine with electronic ignition will idle slower, and they can easily be started by hand.

The G26 and CRRC are both good engines, the Fuji, not so much.

ggraham500

My Feedback: (4)

I fly my H9 1/4 scale super cub with a super-charged YS-120 .. flys great. You could also use a Saito 180 or a 30-50 cc gasser. I'm finishing a 22lb Lift Meister (huge 105in wing span) and using an older 50cc Byron Mustang engine. It would fly aboy the same as a 1/3 scale cub.

w8ye

My Feedback: (16)

I would like to see a picture of a Turbo charged Y-S 120. I have seen a lot of Y-S 120's but never had the pleasure of seeing one with a Turbo-Charger?


A Zenoah G26 will give the Cub a whirl

tripower222

My Feedback: (5)

Any one who may be using one of these engines please post your static rpm with a 16x8 prop if you know what it is.

Checklst

Turning a 18/6 Master Air screw at 8970/9000rpm on a G26 mag version. I do run an Abbell single stack muffler.........it raises the rpm's about 800 over stock......but it's loud!!!!
This is the best motor on your list for sure, only down sides is the weight and on your plane it's not a problem. The mag starts easy on a starter........my mag is well tuned and can be slap started in about 6 flips/slaps................starting a new not tuned mag by hand can be a headache for sure.

This motor like to start wet.........plenty of fuel,choke it well for easy starts.

Good luck.

arobatx

I'm going to agree with those suggesting the Zenoah. First hand experience with a 20lb Decathlon w/floats. APC 16x8 / 17x6 on OEM muffler is OK, but you could also run a good 18x6 with something like the Bennett, or Abell exhaust diverters. The zenoah will last forever, parts are readily available if ever needed, they won't cost you an arm and a leg, and there are many aftermarket parts available should you ever want to 'play' with it a bit. With one of the aftermarket diverters, and the APC 17x6 you could see 9600rpm, a bit less with the 16x8, and about 9000 with a good 18x6. Since the standard electric starters will easily start the 26, I personally wouldn't worry about getting the EI version. Even if a project down the road warranted your interest in EI, I wouldn't go with the OEM EI unit, I would convert it on my own, with Cunningham's or CH's circuit.

NM2K

My Feedback: (14)

If you sat down and calculated the airspeed of the model flying with 6" of pitch at 6700 rpm, you might be surprised to learn that that combination is flying your Cub at just a hair above stall speed. I would drop to a 15x10 or 12 and then reset the engine's needles.

You might discover that you do not need another engine at all. Just because the engine peaks out at 6700 rpm, doesn't mean that it can't pull a heavier prop without losing much rpm and providing a huge increase in performance. Gassers are a bit different in this regard than our old standby glow engines. I wouldn't give up on this engine just yet.

While some of the other 26cc engines you mentioned "might" be a little stronger, what you will really need to make a substantial difference is an increase in displacement to 40cc or greater. This assumes that you have tried my prop recommendation and it wasn't enough to make you feel warm and fuzzy. I would even consider a Turnigy 52cc engine. Good luck.


Ed Cregger

NikolayTT

It seems that I had similar dilema to resolve some time ago and I made my mistakes. Just to share what I learned:
1. McCulloch 28cc from leaf-blower turns APC 17x6W at 8000-9000 rpm and weight above 1.5-2.0 kg with magnet
depending on how much "flesh" one cuts from the body.
Replacing the magnet at this small(!) gas engine seems not efficient because the battery is not much lighter than
the flywheel, similar is for Zenoah etc. and needs care to be charged while the flywheel is "permanently charged".
Using a starter is not such a bit deal; most of us have it and use it unles the engine is so well tuned...
2. For each type engines there is an OPTIMUM displacement and word 'optimum' here is going to cause unger if not
clarified; it is quite personal "optimum". For me ALL BOILS DOWN TO POWER-vs-WEIGHT Ratio unless there are too
many personal other reasons:
A) Glow Engines have their optimum at 26cc developed for F3A. Below that they are a bit too heavy and above that
they eath too much fuel (about 2.5 times more than gas ones.).
B) Gas Engines seems to have some optimum at about 80cc. 50cc is still too small and 100cc gets a bit too big.
After experimenting with toooo many engines I am about to try to sell most of them and retain the only 26cc
and to not invest in 80cc-gas - it is leading to too much Side-Costs (model, servos, Car to transport it, and the
Smell to save it at home is a problem beside the Fire hazard which is pretty much there when gas is involved.)
C) My side"-menu" has bunch of 15cc and few 35cc all glow.
Surely my Gas McCulloch will have ot wait till I play enough with the Glow ones and they are not so "oily" if
pipe is taken to out of the tail of the engine. Surely I also like the simiplicity of the Glow - that is why so many
are with Glow...
Well, I will appreciate if someone tells more technical reasons why one should go gas if he wants to stay on
modest budget ?
Cheers, Nick

dogshome

The McCulloch and similar mag engines are very low powered. I ran a 16*8 on my 83" WOT (very light, sport not scale) and it was just about enough to fly it. It's got a DL50 on a pipe now and it's like a big shock flyer in 3D

A 105" 18lb (EEEEK!) (Double EEEK! 18lb!!!?) Cub would be better on a 40cc, preferably with electronic ignition. The 26CC aircraft engines do have more than the stock trimmer conversions, but I don't think that will convert the plane you have from 'lumbering' to 'sprightly'.


Why gas? Usually the best tickover, less oily mess and more interest [8D]

ggraham500

My Feedback: (4)

Meant to say super-charged. All YS engines are supercharged and scream!

http://www.geistware.com/rcmodeling/glowpower/ys120.htm

tripower222

My Feedback: (5)

Thanks for all your input here is what I came up with after soaking up all your info


With the use of this calculator someone posted for me in anothe post. (very cool by the way) check it out<a href="http://www.mvvs.nl/prop-power-calculator.xls">

http://www.mvvs.nl/prop-power-calculator.xls</a>

With the prop I was using a 16x8 apc at 6600 rpm I should have been getting about 8.2 lbs of thrust on an 18 lb airplane (puke) im suprised it left the water

If Zenoah advertising is accurate they say the g26 will turn that same prop at 8900 rpm thats about 15 lbs of thrust. Almost twice as much, I would think thats enough.

I think if a few people can confirm that I would really see that kind of rpm with that prop on the Zenoah thats what i'm going to use.

Thanks again to all for your help.

arobatx

It will turn that prop at about that RPM with the crappy OEM exhaust It will be quiet though....replace it with the Bennett or Abell Rc exhaust diverter, and it will do much better than that.

AA5BY

Yes on the G-26 as a good choice. Electronic ignition will yield easy hand starting and the blessing of not having to fool with a heavy flight box with starter and battery. The only shortcoming of the G-26 is the ignition is power hungry so right out of the box, consider changing to plug-n-play CH ignition rather than investing in high mah ignition battery.

The power difference between the conversion and Zenoah will be dramatic. There are other choices but you implied that you want a rock solid reliable engine and Zenoah is that.

tripower222

My Feedback: (5)

Got my g26 from Horizon Friday and mounted it WOW WHAT A DIFFERANCE!!!! Before I could place the float plane in the grass and run full throttle and it would sit there. Nowit takes off across the yard. I think if the grass was wet it would take off. thanks for all your opinions.