Pelle Gris

New time Moki owner here.

I have been adviced to keep the rpm´s way down to avoid overspeeding the engine in the air, something like 3400-3600 full throttle on the ground. I´m planning on using a 32x20x3 on my own Moki, and depending on blade shape this should spin about 3500 +/-. A SEP 34x18x3 was quoted as spinning 3400 rpm which minimizes the chances of overspeeding the engine, and provides the best sound in my opinion.

According to Pé´s Excel spreadsheet a 36x20x2 loads about the same as a 34x18x3 so that´s where I would start.

Props in those sizes can be had from SEP and Fiala and possibly elsewhere.

Maxam

My Feedback: (62)

J Tab, About a year or so ago I asked Gotz to order me a couple of SEP 33x16 laminated for my 215. The 32x18 made landing difficult because my two planes are real floaters (Yak 55SP 37% and a super Flyin King). I was concerned about airspeed but it turned out the performance on the planes was improved. The Yak now will accelerate going straight up! It still can fly very fast at level orientation. It is light at around 30 pounds. 4000 rpm on the ground and I always throttle back on the down lines. -Tom
P. S. It is a really good airbrake when throttled back and sounds really cool when the plane is slowing down from a high speed. I got a Kolm EZ 67. What a killer engine! Extremely high power with very low vibration. 6000 rpm on a 24x12.

Lormuhl

This is a pic of the 32-16 3 blade fw prop/spinner on my 42% yak.The cowl is 16" in diamiter and the testing is for the fw190. Again the 33-16 2 blade sep wide blade is the one I fly with

Lormuhl

This is a pic of the 32-16 3 blade fw prop/spinner on my 42% yak.The cowl is 16" in diamiter and the testing is for the fw190. Again the 33-16 2 blade sep wide blade is the one I fly with

wphilb

My Feedback: (10)

I have the new Rainbow Tronic ignitions on my Moki 150s, and despite my best efforts with zip ties the ignition sensor lead worked a bit loose and found the hot collector ring:


So I hit the local auto parts store for this:



15 minutes with elec tape, scissors and a heat gun:



And back in place, held down with an industrial zip tie:


Seriously consider something like this, I was sure I had mine locked down and in ten flights it shimmied just enough loose to hit that frying pan of a collector ring and those wires are like 28 gauge? Not a lot of insulation in the way. I had spiral wrap on it and that melted through as well.

Whit

Lormuhl

wphilb

if you wrap the complete exhaust ring, there is no chance of burnt leads. I used the exhaust header wrap of 1" type. It keeps heat in the exhaust system, which is good for smoke system and also keeps cowl cooler. Good idea on the repair.

wphilb

My Feedback: (10)

I like it! Where did you get the wrap? Can you post a picture of the package / product?

Whit

Lormuhl

O reilly Design Engineering part # 010107 1" wide

TonyBuilder

My Feedback: (11)

Great idea, thanks.

TB

wphilb

My Feedback: (10)

Thanks for the info!!

Was it self stick or did you have to use any sort of bonding agent??

Whit

Lormuhl

no bonding agent, Tight wrapped with stainless safety wire.

rbgetz

I was curious if you see a little higher Cylinder head temps with the muffler wrapped? does the unwrapped muffler dissipate some the heat??

TonyBuilder

My Feedback: (11)

Hey guys, I wanted to see if I could get a consensus on a few things. I'm sure it is all buried in this thread but no way to read it all.

1st how many of you guys are using fuel pumps, or not?
2nd are you guys finding a 2 blade prop works better then a 4 blade or is the 4 blade better with all the tourqe?
and lastly what ratio oil mix, sinthetick or reg oil.

I have a Moki 180 still in the box for a project later this year.

thanks

TB

Lormuhl

rbgetz

After lots of temp testing before and after the wrap, i found the cylinder temps are slightly lower with the wrap. When the engine was shut off, I found the unwrapped exhaust produced lots of heat enough to cause concern in the fiberglass cowl, therefore after the wrap, I noticed the cowl was cooler, the smoke oil was completly vaporized and the cylinder temps slighty cooler.
My yak and fw190 are both baffled, run pumps and a air filter.After much testing I will not run a moki without them.
I found if the main needle will not make the engine run rich over 3/4 throttle, then the fuel system or carb is compromised and therefor runs the risk of engine damage. I use Amsoil Dominator at 50:1 with one ounce of sea foam per gallon. Last week, pulled plugs from yak 250 and the plugs look perfect and the top of the pistons look new, and this was after about 50 flights.

rbgetz

Lormhul...
Great response. After seeing your initial post I did some research on these wraps and sounds like you're testing is accurate. I was also concerned that the wrap might block some air movement over the lower cooling vanes on the heads. but doesn't seem like that's a factor. I'm definitely going to give it try.

rbgetz

HELP... Oh well... I was getting ready to maiden my 3W Bearcat with the Moki 300. I'm running a APS Fuel pump at 5.9 volts. I've started and ran this setup once before and ran fine. today I went to start and the engine gave one short "chug" but wouldn't start. I started to smell fuel but couldn't figure how it would have flooded so quickly. I checked my needles and the settings are as Gotz suggested to start with 1.6 H and 1.2 L. but haven't tuned yet, that was my goal today before the maiden. I removed the engine and fuel had flowed out the carb and completely saturated my K&N filter and was dripping from it, enough to create a small puddle in the fuse... I tested the lines and ran the fuel pump and pinched the line to the carb to see if the return line was working.. All OK there. talk about frustrating!! Any thoughts would be greatly appreciated.

samparfitt

My Feedback: (43)

Thanks for the confirmation.
Back in 2010, I wrapped my Moki 250 for the F4U figuring it would divert hot air from the cowl, also, figuring, it couldn't hurt!
The temps always were reasonable after a flight.
Did the same with my P-47.

Maxam

My Feedback: (62)

RB I have had this happen before. The pump has a fair amount of pressure and if a tiny fragment gets caught between the needle and its seat in the carb, this will happen. You will most likely need to remove the carb and take off the pressed steel diaphragm cover exposing the delicate needle lever, needle and the spring. The single screw that holds the needle lever pivot will need to be removed so these parts can be removed and cleaned as well as the needle seat. This is tedious as the spring can sail off into the wild blue yonder. It is also hard to put this all back together if you have no prior experience. The are two very good Walbro tutorials on youtube that are helpful. A magnifying glass is helpful. -Tom

rbgetz

Excellent Tom, I'll make sure to take my time and wear my mag glasses. Just trying to get the Carb of the back of the moki is a challenge itself.. I spoke with another RC'er from our club and he thought the same thing or that the actual spring itself my be faulty. I'll definitely check that needle to make sure it's clean.

wphilb

My Feedback: (10)

To answer for myself, running two early SN Moki 150s,

Fuel pump, rainbow tronics ignitions, 50:1 with Redline, one oz Seafoam per gallon, 28x14 props.

Whit

wphilb

My Feedback: (10)

Lormuhl,

I just talked about this with Gotz on the Joe Nall flight line.

We wondered if you were able to wrap this on the engine or did you have to remove the collector ring first?

If you did it in situ, which makes the most sense to me, you must have nimble fingers!

Whit

Jaketab

My Feedback: (2)

Hello,

On the subject of the iridium spark plug for the Moki, I acquired one to try in #3 cylinder in hopes of bringing the cylinder up to temp quicker.
The plug was labeled "DLA". The supplier believes it is the same version distributed by RCExel???
I saw no difference in performance. The #3 cylinder temp still lags behind the others at start up. It takes about 5 minutes for the cylinder to come up to temp with the others.
After 5 to 10 minutes of warm up, performance was the same as the Denso plug previously installed.

Regards - J Tab

Maxam

My Feedback: (62)

I was at Joe Nall Tuesday and Wednesday. Fair number of Moki's flying. Beautiful facility. There was a Cessna Bamboo Bomber with twin Moki's. Sounded great!! There was also a CARF Corsair with a 250 that sure was impressive. Incredible jets too. -Tom

Jaketab

My Feedback: (2)

Getting ready to maiden a new Delro Models Turner W4X with a 250 and older top hat ignition and fuel pump.
Stihl Ultra at 45/1 with 90 octane no ethanol gas. Voltage regulated to 5.5v. Motor is not new.

Some issues with the motor I would like a little help with.
1. Running on the ground with the cowl in place, I get a lean condition - possibly as result of heat build up in the cowl.
2. The motor runs like a gyro except at the mid range 2500 - 3000 rpm range where the motor shakes like a wet dog.

When running without the cowl the motor does not sag at max rpm. After about 5 - 7 minutes running with cowl in place, that is when I am getting the sag at high end.
The cowl has baffles in front of the motor and I have 4 vent louvers around the cowl. I will be installing 3 more louvers.
As for the 1st issue, should I expect better cooling when the plane is in the air as opposed to running on the ground ???

As for the 2nd issue, no amount of needle chasing will completely cure the shaking at mid rpm. Current setting for the needles is H - 1 1/2 and L - 3/4.
Since this motor has the older ignition, could that be the cause mid range issues? Is the voltage input a possible cause?

Thanks for any suggestions.
Regards - J Tab

TonyBuilder

My Feedback: (11)

I don't know much about Mokis but just in general I don't think you have enough exit cooling air.

One solution would be to move the cowl and engine forward to open up the cowl.

TB