blhollo2

My Feedback: (278)

I'm looking for the best performance with a zenoah G38 on a Giant big stick..anyone have any suggestions? I'm currently turning a 17x6 and it swings it with ease...

av8tor1977

My Feedback: (6)

I would probably use an 18 x 8 APC or one of the good brand (Zoar, etc.) wood props. If you don't want as much speed and want it to slow easier for landings, you probably go to a 20 x 6, but the Giant Stik doesn't really have enough room for a 20" prop, even with 4 inch tires...

AV8TOR

Super08

My Feedback: (2)

To use a 20" prop on it as I did you need to set it up as a tail dragger and use larger wheels. I had 4.66" antique Dubros on mine. I used a 20x8 on a 43cc, it flew great.

blhollo2

My Feedback: (278)

does anyone know how to find out the thrst of these props?

Super08

My Feedback: (2)

http://mvvs.nl/prop-power-calculator.xls

NorfolknGood

Slow flying aircraft 20" X 8", faster WW2 type 19" X 10" both Menz. Nose overs will displace or bend the crank easily enough on a G38 with a wood prop let alone a nylon, G38 runs better with wood anyway.

blhollo2

My Feedback: (278)

its got a 17x6 Vess prop on it now, i feel like it needs more thrust so would a 18x6 or 18x8 be best? extra speed is a good thing, but over all I'm looking for more vertical

vertical grimmace

My Feedback: (1)

I think to start with you have to use a high quality prop. I have been chasing "the" prop for this engine for a while and at least for my large 1/4 scale Fokker DVII I have settled on the XOAR 19-8. A good 20-6 might work well also, but it really depends on how you want to fly. The power to weight is not very good for this engine but it works great for scale, trainer type of applications.
Give the Xoar props a look and maybe try an 18-10 and definately the 19-8.

frieshoo

My Feedback: (20)

I would put a 18x8 Xoar laminated prop on it.... It needs to turn up to get in the power.

Another option I have tried is APC 18x6W.

w8ye

My Feedback: (16)

I used to fly at a field that had a lot of the old style gas engines like G38's, Quadra 40's and old style G-23's. On the quadra/US engine, everyone used a 18-10 and the did about 7200. But on the G38's they used a 18-8 and the newer ones would get closer to 8000.

The G-38 did better at a higher rpm

frieshoo

My Feedback: (20)

Yeah,

My first gasser was a G38 on a Stinger. I actually liked a Zinger 18x6-10. In those days, we didn't have many options on props. If you found a Menz at a swapmeet you hit the jackpot.

RR24

I have the G-38 on a Midwest AT-6, and was planning on using a xoar 18x10. Do you fellows think that will be a good mix, also about what RPM should one see with that prop?

Ralph, anyone?

ccostant

My Feedback: (38)

I have a G-38 that's pulling a Hangar 9 P-47 (~19 lbs) around without any problems. I'm using a Mejzlik 18x10 prop and get around 7200 rpm on the ground. I think the G-38 will haul that Midwest AT-6 around very well. I would expect the rpm numbers to be similiar with the xoar prop.

RR24

Thanks for your input, I think the AT-6 will come in around 16lbs. It has flaps so should help it slow down.

mrbigg

My Feedback: (21)

This is what I use on my 38 and it spins it right at 7,700. Flys my DR1 just right. It came with the engine when I bought it so I tried it out. Conventional wisdom says I should need a lower pitch on the triplane, but it flies and land really nice, so why switch?

[link]http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXAA52&P=7[/link]

RR24

Thanks just added that to my wish list from Tower

RR24

I ran the used G38 on the test stand today and here is what i got with Xoar 18x10. The best i got was 6800 rpm, and both needles are at about 1 turn out to get the best rpm and transition

the Wasp

My Feedback: (1)

the Carb on the G38 has a Bleed Hole on the High Needle, this Bleed Hole will not let the Engine lean-out as we like to tune our Plane Engines, do a Search on "G38 Carb Bleed Hole" and you should find posts on it, the post will tell you how to modify the Carb,,


EDITED
I had a 3W 19x8 on my G38 with a not so big Muffler and I got 7100 Peaked, and 6800 tuned for flight, my 3W 19x8 was 18&5/8" long, 3W props are real pullers,,

to add, if you do a Search you will find many many post on Prop Size for the G38..

RR24

is this the bleed hole you are talking about?

Antique

My Feedback: (4)

That's it...All G38s have this...You can close it up so the high speed needle will act like one..
Normal high speed setting with the bleed hole open is from closed to 1/4 turn open, per the owner instructions.....
Makes it too rich at high altitudes with small props...

RR24

Thanks Ralph!!

the Wasp

My Feedback: (1)

sorry, I had to Edit the numbers in my post above,, I had the number 8800, it should have been 6800,,

to add,,
yes that is the Bleed Hole I was talking about..

Jim

RR24

Thanks Jim, i will give it a try again when i get the chance

wl7cpa

I just got a Dyna-flite PT19 with a new G-38. This is my second G38. I have one on a giant stick. I am running a Zinger 18 X 6-10 prop. I was checking RPM today and was able to squeeze 6400 RPM. I took the needle down from 1-3/8 to 1 turn. Any thoughts on needle setting, RPM, and prop size for this size plane? First big scale with this engine.
Thanks....and Happy Easter.

RBean

I got a Dyna flite PT-19 at a swap meet with a G-38. Couldn't get it to run right with the original carb. I replaced with a WT-433 and the new insulator block so I don't have to use a bell crank. Had a Master Airscrew 18-8 prop. Turned 7,900 rpm. Replaced with a Xoar 18-10. Seems to have more power with this prop. Didn't write down the numbers for it, but I think it was turning about 7,500-7,600 rpm. Plane weights about 18.9 lbs. Power is ok for scale flying. This is my first 1/4 scale plane and first G-38.