Bob Paris

My Feedback: (13)

I'm now breaking in two RGC 20cc gas engines on a Big Stick...and getting them ready install on a F7F from Troy Built models. I would like to go scale with the props and use three bladed props. I'm now using 17x6 props with excellent results and want to know what size three bladed props I should use. Would a 16x7 or 15x8~10 work ? I know I'm am supose to drop one to two inches in prop length and add one to two inches of pitch...but has anyone any experience with the RGC 20cc gas engine and three bladed props ?

If so ... pleased let me know what you recomend.

Soft Landings Always,
Bobby of Maui

karolh

Using a 15x6 would I think be a good starting point, as you will find that choices in 3 blade props are somewhat limited.

Karol

Lifer

My Feedback: (1)

MA has a 15x7x3 that turns my RCGF 20 at around 8k.

pe reivers

The rule is to go 10% down in diameter, eventually add 10% pitch as well.

Bob Paris

My Feedback: (13)

Hi Guys,
Thanks for the information...I'm ordering M.A. 15x7 props and see how they pull. And your correct, there are not many 3 bladed props sold today.
Soft Landings Always,
Bobby of Maui

TimBle

The RCG should be able to turn similar props to the DLE20 so a 15x8X3 MAS or even a 16x8x3 could work. Check the thrust and cylinder head temps with the 16x8x3 though.

darren763

My Feedback: (117)

What three blade props did you end up using and what rpms? I am planning on using these on my next project. Thanks, Darren

Bob Paris

My Feedback: (13)

Ok Guys,
I've run Master Airscrew (M.A.) 15x8 three bladed prop on my RCG 20cc gas engine and pulling between 8400 to 8700 rpm. Just a bit lower then the M.A. 16x8 two bladed "S" series prop I run now...and getting a solid 8900 rpm, with the two bladed "S" Series prop too. I've run two RCG 20cc gas engines now and both are close together in rpm with the same prop. The second RCG 20cc engine actually runs a few rpm more then my first one. I'm very happy with the RCG gas engines and now putting a RCG 26cc engine in a ESM F6F. The RCG 20cc engine may be equal to or a bit more powerful the DLE 20cc and a good $100 bucks cheaper. I'm not knocking the DLE...its a good solid engine and most the club out here fly's them, but for the money you can't beat a RCG 20cc. The only problem you have with the RCG engine is dealing with Hobby King. But once you sort out dealing with them...they do sell a good solid gas engine.

It also depends on what prop manufacturer your using. My RCG 20cc engines will turn a 17x6 Xore (sp?) prop at the same rpm it turns a M.A. 16x8 two bladed prop...8900+ rpm.

A 16x8 three bladed prop may be to much for the 20cc engine...and the 16x8 M.A. prop is what I will be running on my RCG 26cc engine.

Soft Landings Always,
Bobby of Maui

Lifer

My Feedback: (1)

I ran a 16x8x3 MA prop on my RCGF 20. It ran okay but it was working pretty hard. I have since switched to a 15x7x3 MA and it seems a little happier.

RBean

Master Airscrew has changed the design of the 16-8 three blade prop in the last yr or two. My DLE 20 would turn the old one about 7,900 to 8,100 rpm. They thickened the blades near the hub and I think a little more pitch our near the tips on the current production prop, they said to better take the stress of a gas engine as opposed to glow. (I never had a problem with the old prop). New one turns 7,000 to 7,200 rpm. The DLE 20 turns a Graupner 15-8 three blade about 8,400 rpm and a MA 15-7 three blade about 8,800-8,900 rpm. Any will work, but with the new MA 16-8 three blade the engine is working harder and the needles get touchier to adjust. It can lean out more in the air when under a load. Here are some pictures. The Hurricane has the Graupner 15-8 three blade, The P-40, MA 16-8 (old model) and the Tony, MA 16-8 (old model). All have DLE 20s. I have one of the new MA three blade 16-8 but it is currently not in use. Would probably work better on a 26 cc engine.

tailskid

My Feedback: (34)

I'm flying a MA 15/7 on my Pulse 125 with a DLE20 and it pulls the plane around pretty good!