wxman2

My Feedback: (52)

Mick15,

I will be buidling a Scale Wings 1:3.5 this fall/winter. Have you thought about adding a fan to your LA-7 like the real one had?

I haven't got too far into, but Ihave sent out some emails to CNC companies to see what type of price I will be looking at to add a fan to my build. What I am thinking is having it made out of aluminum then anodized flat black. This should help with keeping the engine cooler.

Regards,
John

mick15

I don't think so John, a fan will get the air into the engine compartment, we don't have a problem getting it in, we have a problem getting the air out!

m

wxman2

My Feedback: (52)

M,

I would think it would still help with adding additional positive pressure; maybe... Iguess I will also make a custom air tunnel so that air can exit the exhaust ports. I was already planning on making a custom exhaust anyways for the LA-7.

bokis

Ivé just ordered a fan to my Moki from Airworld,the biggest problem is by far cooling on my FW 190,getting the air where it does some good..
With the prop I use,a threeblade scale prop from Biela ,the chanses of getting air in when it stands on the ground is zero,there is no airflow there when I taxi or just run the engine..
And in the air,whit enough "air out" this fan will help a lot to get the air where it´s most needed,around the cylinders..
Thank´s for a great thread about Moki´s , it´s helped me a lot understanding and answer questions I had about the engine..
Kram,You stated that theese engines have been around for a hundred years and thats true but they also had their share of problems..
The "new" FW 190 produced in Germany have problems with cooling so it´s not so simple as one might think...

butlern

My Feedback: (15)

Anyone have experiene with the SEP line of propellers? Specifially I want to know if my moki 150 will comfortably turn an SEP 27x12 3-blade (turn ~4900-5100 at full throttle).

Thanks

vfrank59

Hello Guys,
I have a Moki 250 and a 32 in, 3 blade, solo adjustable prop. The prop blades are carbon fiber. What should the prop ground RPM be at 1000 ft above sea level for this engine. I am near the maiden in a couple weeks.

I have heard, 3600 rpm to 4300 rpm.

Thanks,
Vern

Straightleg

Vern, 3600 should be about right and give good forward speed.

/straightleg

Detlef Kunkel

Hi butlern,
for a radial like the Moki, I would not recommend a fine pitch as 12" on a fast plane, maybe on a WWI Biplane.
15" is the least to use in my eyes. 17" is better. Otherwise you will kill the engine in flight, with a poor output on level flight.

a very good prop on the 150 for a warbird is the SEP 24x17 3-blade

ram3500-RCU

My Feedback: (221)

[8D]

butlern

My Feedback: (15)

Hi butlern,
for a radial like the Moki, I would not recommend a fine pitch as 12'' on a fast plane, maybe on a WWI Biplane.
15'' is the least to use in my eyes. 17'' is better. Otherwise you will kill the engine in flight, with a poor output on level flight.

a very good prop on the 150 for a warbird is the SEP 24x17 3-blade

[/quote]


Thanks, Detlef.

I am not looking for tremendous airspeed, which is why I considered the finer pitched blades. I only wish to have reasonable acceleration, and some climbing capability.

The model is a large torpedo bomber, so I was really looking for the best balance between largest diameter (more scale appearance) and suitable performance.

Here is a picture:

Detlef Kunkel

Even with that nice Bomber,I would recommend 14 or 15" pitch.
All you will lose is inflight power running a 12" prop, and earn an engine that is permanently over-revving.

butlern

My Feedback: (15)

Thanks,

What then would be the largest diameter that I could use for a 3-blade, 14-15 pitch without over-revving a broken-in 150cc?

From several USA-based distributorships, I only see the following 3-blade props available:

24x18 SEP
24x17 SEP
26x14 Bielia
28x14 Fuchs
28x16 SEP (much too large, I imagine, as these are break-in props for 215 and 250cc)

Perhaps the Bielia 26x14 is the best option for me.

But what do you think of the 28 x14 Fuchs? Too much prop for the 150cc?

Thank you for the feedback!

Noah

koenvlieg

Hello John,

I have the scale wings 1/3.5 with the moki 215. You absolutely don't need a fan. Just buy the moki 215/250 setup from scale wings with the wooden part that is specially made to have the airflow along the cylinders. I open the part from the fuselage where normally passes the exhaust pipes ( also make some big holes in the fiber part, so the airflow can pass directly to outside ), I make the holes bigger where go the two moki exhaust pipes go through and finally I close the oilcooler in the front and make a big opening in the fuselage so the air can go out via the oilcooler. The result is that cooling is absolutely enough and still very good looking. The prop is a sep 3-blate 29*18 about 3900rpm very scale looking and sound. Speed of the plane with this setup about 215 km/h.
As far as I know the real la-7 didn't have a fan, but she could fly on aircooling when the oil cooling system was broken.

fg

koen

ps you did a very good choice to buy this model, it's worth his price !

wxman2

My Feedback: (52)

Thanks koen,

My plan is to also open up the fuselage where the exhanust normally passes and build a custom working exhaust for my LA-7.

goodinmw

Bob, Gary, Warbirdrcr,
Sorry it's taken a while, got tied up with other work....
Continuing to work the Moki 150 #3 cold cylinder-
I've attached some additional cylinder temp data (pdf) from my experimentation.
Anyway, the thermal data is for several runs where I have drilled a small diameter hole in the #3 cylinder intake tube in hopes of bleeding in some air and leaning the #3 mixture. Experimented with .031in , .038in and .047in dia hole.
More or less some success, though not the solution. Happily the hole made for little detectable impact on cylinders other than #3.
Sorry the data is a bit cryptic at this stage- I need to acquire and tie in RPM and throttle setting to the data to get a better picture of what is really going on.
My next steps are installing another intake tube to which I have added a 1/16 nipple, to which I'll run some tubing to a needle valve mounted on the firewall (down low). Picture of hardware attached.
Will add an "as installed" picture when I have it.
Aloha!
Mark

Detlef Kunkel

Noah,
SEP 24x17 3-blade is a very well suiting prop for the 150 in a not too big warbird, for example the smaller scale wings LA-7 or a 2,4 m corsair. The engine is in flight in its opimum rpm range,having a very good power output.


@ Mark,
I think you are looking at the right place, but I doubt if you will succeed in closing that bleeding hole when you stick back on the throttle. You would need a steerable valve for this.
In idle range your hole will do the opposite of helping the engine; general idle rpmwill increase, and no 3 cylinder will lean out.

JRSmith

My Feedback: (47)

Post deleted, posted in the wrong forum. Take care.

Jason

IFLYBVM2

My Feedback: (360)

Hi Guys-Running a 26 x 16 2 blade on my now well broken in 150. Would like to order a three blade 25" from Vogelsang, but after days of trying to get them on the phone I am at wits end. Anybody know who else might stock the 3 blade suitable for the 150 ? I see troy built has a 26" three blade, but not sure about that one. Thanks-Mike Oberst

samparfitt

My Feedback: (43)

3-blades:

http://www.desertaircraft.com/page.php?Page=Mejzlik

Of all the props that I have used, I find Mejzlik the most efficient.

IFLYBVM2

My Feedback: (360)

Thanks Sam-I see they have a 25x12 three blade-do you guys think thats enough pitch for the 150 ? The aircraft is 100" T-28 Trojan. THanks-Mike O

Scott Prossen

Hey Mike,

Since the 2 blade is usually a 26x16 then the logical 3 blade would be something like a 26x15, 26x14, 25x16, and or a 25x14. I would say those would be the mins.
BTW, I am very impressed with the build Denny is doing on your CARF47 at Franks. It's really a nice model and Denny is doing a Smithsonian type job on her!!!

ATB,
Scott

IFLYBVM2

My Feedback: (360)

Hi Scott-Thanks for the reply-I will continue to try and get Vogelsang on the phone -he has the one I need.
Excited to hear Denny is doin my '47 up right for me ! Thanks for the update.
Speaking of MONDO LARGE P-47's, your is most impressive ! Can't wait to see the finished product.
Best-Mike

butlern

My Feedback: (15)

Mike,

Same problem here... I have been trying for 10 days to get someone to answer the phone oat Vogelsang-Aeroscale so I can order the SEP 24 x 17 for my 150cc.

If Goetz only has one in stock, and you get through and place your order first... I'll be damn sad!!!

Will try to call again tomorrow.

Good luck!

Sam, no one else appears to carry sutable 3-blade props with enough pitch (>15). So the hunt continues.

Noah

vfrank59

Send Vogelsang and Email He will get back with you usually in 24 hrs. He is a very busy man, I think He checks his email at 8 am and 7 pm. Great guy to deal with.

Vern

Scott Prossen

He is in Europe right now. Always tough to get him when he's out of the US.
Scott.