TimC

Webra .35: 4000', 65 deg., 15% Powermaster, O.S.#8 plug, Mac's Muffler (6650), 10x6 APC, after 32oz of fuel
11,800 peak rpm

Rudeboy

That's too low... It should do more on a 10x6...

I think you are killing your engine with too much nitro and a plug as hot as that OS #8...

Shim the head, or switch to 5% nitro.

TimC

I tried it with 5% Cool Power with 2 oz. of castor added to the gallon: 11,210 peak. The 15% runs fine with no sign of detonation or over-heating. I'm assuming Webra shims the head for the U.S. market.

TimC

Today was about 100°F. I decided to try an 11x4 APC. Using 15% PowerMaster, it peaked out at 11,700 rpm.

WMB

My Feedback: (1)

Do you have an APC 9x6 to try? I thought the Webra's in general liked to rev a little higher. What plane do you have it in?

Have fun, MikeB

TimC

Here you go Mike, 9x6 APC: 15,450 rpm peaked. This is the highest rpm I've ever run an engine. It sure screams. My computer for some reason won't download the thrust/horsepower calculator avaible on line, even after I installed the required program to run it. I'd be heap grateful if someone would crunch these numbers:[ul]
[*9x6 APC 15,450]
[*10x6 APC 11,800]
[*11x4APC 11,700]
[/ul]
I'm still looking for a good plane to put it in.

WMB

My Feedback: (1)

Thanks Tim. I've got the OS32F that will be going into a Sig Kobra. Your running a little stronger than mine. I am about ready to start covering. Hope to get it in the air soon. I've heard of a 25 size 300 arf Extra. Have heard good things about it, don't remember the mfg.
Take care, MikeB

TimC

Mike, I think I have that little Extra (ModelTech) with an O.S. .32SX in it. It's a sweet little plane and quite a bargain at $80. I like the O.S. fine and wouldn't think of swapping it out for the Webra.

HaveBlue

I ran the figures through, but at normal air density..not sure how much your elevation would effect these figures

9 x 6 @15450 = 87.79 mph/ 1.037 HP/4.07 static lbs thrust

10 x 6 @ 11800 = 67.05 mph/0.704 HP/4.18lbs

11 x 4 @ 11700 = 44.32 mph/0.670 HP/6.01 lbs

TimC

Thanks a heap HaveBlue. MikeB was right; this engine is a revver.

Ernie Misner

Hi Tim, are you still following this thread? Long time no hear from you! I still have an OS 32 and a webra 35 myself. Both need a plane.

Ernie

TimC

How's it going Ernie. I still visit RCU now and then, but I haven't been doing much flying. The .35 is not in a plane. One of these days I'll get fired up on flying again and find a plane for it. I hope things are going well up your way.

RocketRob

My Feedback: (1)

Thanks for the numbers guys. Don't have a 32 but my webra .28 diesel spins a 10x6 (Bolly and APC) 11,900 to 12,100 - havn't run one of the glows yet but will use a 9x6

freakingfast

My Feedback: (3)

These are my notes from years ago, on hind sight I think I was running too much nitro and/or wrong plug (OS#8), because I remember plug life was a bit on the short side. Webra 35 ringed with Macs muffled tuned pipe, running Powermaster 15% nitro.
16,500 with 9X6 APC
17,700 with 8X8 APC

Note, these are nearly identical results to a same setup OS 32 SX. Fuselage(glass F-3D) vibration was higher with the Webra and extra measures were needed to keep the fuel from churning at high RPMs. The break-in process was longer with the Webra.