Ragz

Just ordered a Moki 250 for a carf p47. Cant wait to get working on it. This thread will be a valuable resource.

skymaster68

My Feedback: (4)

Guys, thanks for the inputs last weekend, unfortunately nothing worked and we find that the problem was the ignition, it was not sending any spark to the plugs, fortunately there was another Moki 250 NIB there and we used that ignition, we mounted the engine on a stand and it did start so we will maiden the CARF p47 this coming weekend, once again thanks for the inputs and ideas you gave us.
Brgds
Cristian

Greg Wright

My Feedback: (6)

I received my new Ignition yesterday and was able to bolt it back into the plane and it seems as though it is back in running order.

I'm still not totally convinced that you need the fuel pump and this other thing called a turbulator. I have neither one of these mounted in my airplane and the motor runs absolutely great.

I can hand choke it at an idle throttle setting with about 3 to 5 flips of the prop and then it only takes 4 flips to get it running. It fires on all 5 cylinders and idles at around 500 RPM.

So what is the reason for all these other item's?

Scott Prossen

Moki 400 and Prop performance. I'm hoping someone out there reading this can tell me of a prop that is more efficient than my set up on my big P47. I'm running a standard 2 blade wood prop 38x18 and getting about 4000 rpm. Phil Clark told me of a prop no longer available they ran on Ali's giant Skyraider (bigger and heavier than my 47) that was a 2 blade carbon fiber 39x25 pushing 4400 rpm. The videos show proof that it moved the plane with more authority than I'm getting out of mine. I've tried to get that prop they used to no avail. I have little or no expertise in the prop area so I was hoping someone could help me here?? Thank you in advance!

Scott Prossen

Maxam

My Feedback: (62)

Scott, the SEP props from Germany supplied by Vogelsang aeroscale have excellent performance. I have seen your plane I believe on youtube and yes I see why you have a concern. The large three blade props (carbon fiber) have tremendous performance. It is amazing how two props with the same pitch and diameter can have vastly different performance. I am sure much frustration with large carbon props is the low pitch catering to the 3D crowd. Is a 4 blade solo out of the question?

Greg, Some engines need the pump, others do not. There is great unit to unit variability with the pulse pumps on these engines. As far as the turbulators are concerned, measuring cylinder temps, I have seen over 100 degree temp differences between cylinders on some Moki's. I have brought them to within 5 degrees of each other on my 215 and 20 degrees on my 150. The running qualities were vastly improved on both engines. I have turbulated 3 other Moki's for people and all were thrilled with the improvements. My engines are easy to start too. I met you at Toledo I think. Didn't you have your P47 on display? -Tom

reyn3545

If you're running that solid with no additional hardware.... you are good to go!

reyn3545

I could be wrong... but I think the variations in running quality and cylinder temps are also related to the quality of the ignition coils. I had a 150 that ran OK, but had the typical issues with #3 cylinder. I tried different plugs, a turbulator, a fuel pump, all with varying degrees of success. Then I purchased one of the RainbowTronic ignition units from Vogelsang.... it made an immediate difference. When I removed the old coil assemblies from inside the rear housing, I was surprised at how the wiring, solder joints, etc... looked so poorly done.

I had hoped that the new ignitions would move away from those internal coils, but it looks like they have stayed the same.

jairaksinen

Hello, Last weekend my Moki 250 quit on me suddenly. I was doing a full throttle low pass when the engine suddenly quit. The propeller was rotating until the plane crashed just 10meter from the runway. The Moki was in 1/4 scale F4U Corsair with baffling. I also have the fuel pump installed which was working afterwards and the tank was also almost full. When I checked the ignition at home it was firing on all cylinders. Anyone experienced the same? What could be the reason for it? I my self have no other explanation than overheating since it was a rather warm day, about 30°C with scattered clouds. I have not yet tried to run the engine, but will do that soon.

Maxam

My Feedback: (62)

Usually an overheating engine will start to slow down then quit, not suddenly. Possible intermittent loss of power to your ignition? Still have all pushrods? Does the engine turn over smoothy. A guy in Germany was screaming his 250 in a Corsair no less and it suddenly stopped due to crankshaft failure.....eeek! -Tom

jairaksinen

yes the engine is still easy to turn around and all the pushrods are still there. I have a Solo prop 3 blade 32x20", it takes around 4000rpm static and unloads to about 5500rpm in the air. My brother mentioned his Moki also quitting from full throttle when running it on the ground. and it fires instantly when restarted. I am going to replace the ignition and the kill switch but it wold be nice to know what can cause it. Anyone know what is the max temp for ignition units in general before they start to malfunction?

I also had the time to turn off the ignition and back while the prop was rotating and it did not fire anymore. So can the ignition die of overheating and when it cools it will start working again?

rk212

If anyone is interested i have a spare MOKI150 ignition unit available in perfect working order.

Would prefer paypal please and can ship globally as doesnt weight much

$150

PM me if interested please. Kind regards

Jet Nut

Gday jairaksinen. I have been flying my CARF Corsair for about 4 years now. Many many flights and while sometimes the engine may not be quite "on song" either rich or lean, it had never totally quit until about 5 months ago. I was up with a few other aircraft and was quite away from the field when I noticed that the big girl was no longer interested in flying. I aimed her straight back toward to field and only just made it back with minor damage to the airframe. I broke my solo prop and also bent the shaft. Prior to that, I had replaced the ignition pack and what I had found was that the pins on the new pack had a bad connection. I can't imagine any other reason why one of these engines would quit completely other than no fuel and you mention your was almost full. I have had rods fall out during flight and rockers break and although not happy, the engine continued to run on the remaining cylinders and bought her home ok.

So, my only input can be what happened to me. I hope you find the reason mate.

Lee

jairaksinen

I've also had cylinder cranked when couple of bolts failed, lost a exhaust rod, and intake rod. But still to engine kept on running. And now it just died on me with everything in place. I started wondering what happens when the actual coils get overheated? Can they malfunction in this manner?? My landing landing was not so happy one, broke the fuselage and the wing center section. But this is the Don Smith corsair so easy to fix with some new balsa. Luckily wing folding mechanism did not break.

reyn3545

Holy ****e... it turns a 32x20 3-blade?

I've got a 250 in a Pitts, using a 2-blade 32x18... it's got plenty of power, but a little slow... I wouldn't ordinarily think of a 3-blade for more speed, but more blades and more pitch would be a different story!

jairaksinen

Well the 20" pitch is from the Solo prop dial manual. I tried to calculate it measuring the angle of the blade and got 19,8" pitch so I suppose it is in the ball park. I actually went further on testbed to ~25" pitch. if my memory serves it took 3600 rpm. I did have a MenzS 32x20 two blade and it took 4350rpm static, so adding a blade dropped only 350rpm. Also 36x14" two blade takes 4300 rpm.

Moreover, The 3-blade prop I have from CARF weights 970grams. So going with a lighter one might improve the situation.

reyn3545

Do you feel like the plane is flying fast/well enough with the 32/20 setup? How much does the plane weigh?

I've ordered a Solo prop for my CARF Pitts, 32 inch, 3-blade, but I think I'll probably have the pitch set in the 16 to 18 range... The Pitts weighs almost 55 pounds.

jairaksinen

My plane weights about 60 pounds. According to the telemetry the plane goes close to 200kmh level flight. So yes it does flies well and fast enough. With the menzS 32x20 two blade I recorded 234kmh in a shallow dive and about 15kmh ahead wind. but the prop unloaded too much in the air causing very heavy ripping of the blade tips.

Scott Prossen

Hey guys look what the doctor has in stock for us. Got mine in two days. Get ahold of Dr. G at the website listed and get yours going! Thanks G, you're the best. Love the baffle!



http://www.teamaeroscale.com/

reyn3545

Nice! I didn't know there was a 300 on the market. And I like that baffle template. I wonder how close it would be for a 250, or if there's one available for the 250?

I ordered a Solo 3-blade prop a few weeks ago..... only to find out that there's a 4 - 5 month wait.... yikes!

jairaksinen

At least Airworld.de sells baffling for Moki

http://www.airworld.de/Englisch/Index.htm

Also CARF models sells the same SOLO 3blade hub with carbon blades. They seem to have plenty in stock.

reyn3545

Thanks... I'll check into CARF. It's going on a CARF Pitts. I would prefer the clear coated wood blades just for looks, but we'll see....

Scott Prossen

Another nice thing about the wood blades..........should you have an unfortunate happening and snap off some blades my belief is they give much less stress on the crank shaft than a CF prop would!
Been there and done that, the crank shaft and repair is far more expensive than the wood blades.

Scott Prossen

I'm pretty sure Dr. G has them immediately available for all the Moki's. Send him an email [email protected]

reyn3545

Will do.. thanks.

Maxam

My Feedback: (62)

They now have a Moki 350 seven cylinder now too. -Tom