rfenster

My Feedback: (49)

I spent the better part of the day running it and breaking it in.
Here are the numbers with Omega 15% and a short plug. I wanted to use 10% but I am out. This is using the stock Webra 40/50 sized muffler.

M/A 11x7 14,000

Zingali 11x7 13,800

M/A 11x6 14,950

M/A 10x7 15,800

Not bad for an engine that is basically in a 40 sized case.
Pics show the muffler used and the 55 between an old speed 50 and a RE Speed 60 for size comparison.

CustomPC

Not bad,

For Comparison, i get 13,600 with an APC 11x7 on an OS .55AX with UltraThrust muffler using 15% nitro and 15/3% Synth/Castor oil.

rainedave

My Feedback: (1)

Yes, those are impressive numbers. Would you mind taching an APC 11x7 for comparison's sake? I'd like to see how your engine compares to some .61's.

The 14,000 with the MA equates to 1.45hp, so I'm guessing it will turn the APC just a tad over 13,000 (same HP).

Thanks,
David

rfenster

My Feedback: (49)

David, weather permitting I will run that one tonight along with an APC 10x10, 8.75x8NN, 12.25x3.75 and a few others. Any other sizes you would like to see?

rfenster

My Feedback: (49)

Here are some more numbers. Rossi R5 plug, Standard muffler, 15% Omega, 75 degrees and humidity of about 73%. Yesterdays numbers were with a humidity of about 50% and a temperature of 72 degrees. All readings were done without a spinner and safety nut only. I don't know if that makes a difference or not. I might try some more readings with the pipe and header I used on my Speed 50.

M/A 11x7 (for comparison of yesterday) - 13,900

All of the following are with APC props:

11x7 13,400 (I was hoping to beat the OS 55 with the Ultrathrust but I guess it wasnt meant to be. [])
10x10 12,240
10x9 13,350
10x8 14,350
9x10 15,100
8x10 16,320
9x9 16,200
8.75x8.00NN 17,800

More props of different makes:

Rev up 11x7 13,450
Zinger 12x6 11,250
Zinger Pro 12x7 10,230
Zinger Pro 13x5 10,740
TF Wood 13x6 9100

The new Webra carbs have a bore of .372" (plus or minus a couple of thousandths) as opposed to the .310" bore of the carb on my Webra Speed 50. When using the larger props a smaller bore carb would have helped a little I think.

An interesting side note. When I was testing props the first APC 11x7 I tested I only got 12,400. I tested it again in the middle of the rest of the testing and got the same results. Remembering David's comment about the RPM's I should get with that prop I tried a different APC 11x7 and got 13,400. I am assuming that the first prop was actually an 11x8 and incorrectly stamped 11x7. ???

OK fellows, that exhausts my usable prop supply for this engine. Your mileage may vary.
Rob

CustomPC

Nice work,

They're good numbers with a factory muffler. I'm sure with the Ultrathrust you'd beat the OS and then it would be an apples to apples comparison.

That muffler looks fairly short and squat which tends to favour higher rpms.

I'm a fan of OS and Webra's. I had a Webra .50GT which pulled really good numbers with a 10x6 running straight fuel with 20% castor and no nitro. I sold it to a clubmate who wanted it for racing. I tried to buy it back off him a few weeks ago and he said it's too good to give up.

I'm about to buy a Webra .91 P-5 today. I've been wanting one for a while and now that i can finally get one i'm looking forward to playing with it.

rainedave

My Feedback: (1)

Thank you Rob for the first rate testing!

I only have one APC 11x7 left that isn't dinged or chipped. Now I'm curious to buy some more and see if I find and difference between them. That 12,400 does sound like what an 11x8 would typically turn.

At any rate, you have a very strong engine. That it's doing this with the stock muffler is even more impressive.

It makes you wonder why Horizon stopped selling Webras (or, why people weren't buying them).

David

rainedave

My Feedback: (1)

I've noticed that the 55 P5 GT is listed as having the same power and rpm range as the Speed 55 GT. Is the P5 simply a newer version?

http://www.webra-austria.at/motor.ph...r=AERO&lang=EN
http://www.webra-austria.at/motor.ph...r=AERO&lang=EN

http://www.mscomposit.com/motors/nit...5-gt-aero.html
http://www.mscomposit.com/motors/nit...5-gt-aero.html

Thanks for any info on the internal differences between these two engines.

David

CustomPC

I think the P-5 stands for the ammount of transfer ports.

I always thought the P-5 series were designed more for torque instead of rpms, and that is probably why the carb inlet is smaller than the Speed series, but rfenster's numbers suggest that the .55 at least can be a revver.

rfenster

My Feedback: (49)

Thats a good question. They both have the same bore and stroke and the same carb. I bought mine last month from Webraus.com. That is the only 55 he has listed on his site. Maybe Dave from that site or one of the other gurus can chime in. Actually CustomPC my P-5 has a larger bore carb than my Speed 50. I think, but not sure, that the Speed 61 and 50 both use the same carbs.

rainedave

My Feedback: (1)

My Speed .61 has an 8mm TN carb.

According to the Webra site the 55 P5 GT comes with the 1030/116 which has a 9.5mm throat:

http://www.webra-austria.at/motor.ph...RETTOR&lang=EN

David

rainedave

My Feedback: (1)

I ran my Speed .61 with a Dynamix carb today - a very easy carb to set up - and gained a few rpm: 13,044 with an APC 11x7. It's a rebuilt engine with a fairly new ring, so I'll probably get a little more as I continue to run it. That's actually a bit stronger than my Tower Hobbies .61 which is supposed to be one of the more powerful sport sixties.

David

rfenster

My Feedback: (49)

David,
Were you using a pump with the Dynamix? The one that I have will not draw fuel no matter how far out the NV is. I understand that they need a lot of pressure or a pump. Is this what you found?

rainedave

My Feedback: (1)

No pump, just muffler pressure. I found the high speed needle to have a wide adjustment range. I could richen quite a bit. I have also heard people say they need a pump, but mine behaves just like a TN.

David

Hobbsy

My Feedback: (102)

Dave, here is another DynaMix that draws fuel just fine using only muffler pressure. This is a brand new .91 I found a whaile back. I have 3 .91s now, two ringed and one ABC. The ABC is a Diesel conversion.

Also a shot of my Webra Dykes ringed .50 Diesel conversion turning a Graupner 12x7 at about 9,650 with the stock baffled muffler and 9,950 with the Bisson pits in the picture. Its a fine Diesel.

rainedave

My Feedback: (1)

Today was actually the first time I've operated a Dynamix. I was very impressed with how easy they are to adjust. I just wish mine had the stop screw in the end of the slide (it will fall out if I'm not careful).

Dave, you and I both enjoy running and testing engines on the stand. I'm getting together with av8rsodt this weekend to beak in his NIB OS .50FSR.

Good to know the ST header fits the Webra .91 case. Did you have to elongate the holes any?

Kweasel

My Feedback: (29)

I have some older APC 11-8s that tach higher than their newer 11-7s.