RunRyder RC Helicopter Topic - New 90 size gas engine from webra

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Engines Plugs Mufflers Fuel > New 90 size gas engine from webra

bagobitz
Veteran
Location: saddleworth,lancs,UK

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forgot to say, FANTASTIC CANOPY

I don't really go in for that artwork sort of thing but that's a real fierce birdie

04-21-2007 Over year old.

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bluefalcon
Heliman
Location: Bonny Hills, NSW, Australia

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Bagobitz, thanks for pointing out the error of my ways, just a temporary brain fart, I am in fact running 33:1 at the moment. The old brain doesn't function quite the way it should when I get tired.

What you are suggesting is much the same system that I used on an OS supercharged 4 stroker a while back. If I combined that with a break tank to catch the bubbles and return them plus excess fuel to the tank you might have given me an answer. Thanks muchly for the input, it is always appreciated.
I too am a bit perplexed by Webra's aparent unwillingness to get involved with what are, essentially, their problems. As you have no doubt read earlier in this thread they do not go about helping us with any enthusiasm and without considerable prodding.
I am still waiting for an answer to the e-mail I sent them. Unfortunately there is no Webra distributor in Australia and it's a bit hard to put pressure on someone on the other side of the world. While I am very happy with my engine so far I'd have to think very carefully before buying another one from them.

04-21-2007 Over year old.

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bluefalcon
Heliman
Location: Bonny Hills, NSW, Australia

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Bagobitz, I've given your idea some more thought and I don't think it will work with this set-up. Unfortunately the line pressure where the bubbles are being formed is lower than the tank pressure making it impossible to return to the tank from that point. Thanks anyway for the input and if you have any more thoughts on the problem I would love to hear them.
Nadman, couldn't post the head speed because I couldn't start the engine. The spark looks a bit weak and I'm hoping it isn't the same trouble that Fixit had. Soon as I've figured it out I'll post it. Very disappointing and perplexing since it's been so easy to start up until now.

04-22-2007 Over year old.

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bagobitz
Veteran
Location: saddleworth,lancs,UK

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yes,a circulating system will only work with a positive-displacement pump.-a pressurised system will still need a pumping-force to return surplus fuel to the tank.
am I right in assuming a "perry" is a peristaltic pump? If so, that should work,provided it's flow-capacity is greater than the engine's burn-rate.
How about a very thin copper or brass section of fuel-tube (something like an old ballpoint-pen refill) with standard (silicone-rubber?) fuel-tubing at carb and tank-ends to make the connections.
the thinking here is that 1-the metal tube would get air -cooling and keep the fuel cooler.
2- the thinness would mean a faster flow-rate through the tube,minimising the possibility of the fuel absorbing enough heat to vapourise.

It sems that most of the problems are caused by inadequate cooling and I think this vapourising in the fuel-delivery pipes is one of those problems.

04-22-2007 Over year old.

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AirWolfRC
rrProfessor
Location: 42½ N, 83½ W

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After a bit of checking, I find that gasoline component fractions boil anywhere from 40ºC to 200ºC, depending on the fuel. If your fuel path is getting to 75ºC then, yes, expect bubles.

04-23-2007 Over year old.

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bluefalcon
Heliman
Location: Bonny Hills, NSW, Australia

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Just finished with the motor. It now starts first kick and runs smoothly as it has been. The weak spark and difficulty starting was apparently caused by a poor connection between the high tension lead and the ignition module so I'm a happy little vegemite again

. Still getting nowhere with the regulator, I've solved the heat problem by mounting it to the chassis with a heat sink but the bubbles are still there. It's looking like the diaphragm has got to be the culprit but I can't see even a tiny pin hole in it and I've checked it with a jewellers loupe and a light source behind it.

Still waiting for a reply from Webra!!

Maybe they're very busy at the moment?

04-23-2007 Over year old.

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nadman
Senior Heliman
Location: ...

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Had a short flight yesterday. Still at 260-285F. With the weather warming up here I don't think I can run the engine for much longer. Raptor cooling is not good enough for this set up.

I have some brass line and I will try bagobitz idea. i.d is the same as regular fuel line so flow rate will be the same. With the brass pipe I should be able to get a reading on actual/approx fuel temp (I hope).

I am also still waiting for a reply from Webra regarding my regulator (2 weeks).

04-23-2007 Over year old.

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bluefalcon
Heliman
Location: Bonny Hills, NSW, Australia

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Pretty much everyone agrees with you regarding the Raptor cooling, while it's adequate for the majority of cases it tends to fall a bit short of the mark when the going gets tough.

260oF - 285oF equates to about 130oC -140oC which is still at the lower end of the scale that Webra gave me. They indicated that I could expect 130oC - 170oC (266oF - 338oF) although I would be getting a bit worried if it got towards the upper end of the scale. What is your average ambient temp over there at this time of year and what is your average max for summer? Average here is about 25oC (77oF) with a max up around 38oC (100oF) and the odd day over 40oC (105oF). On the hotter days it's just too damned uncomfortable for flying anyway.

04-23-2007 Over year old.

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nadman
Senior Heliman
Location: ...

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Webra gave me lower numbers. They said expect 220-240 hover temp.
Above 300F my engine starts to lose power and of course bubbles, bubbles......

My regulator is on its way to Webra.

Summer time temps here are about 35C and max 45C. Now is about 30C and I am at 3800f ASL. I only have few more weeks to do any sort of testing and then I will have to put back the glow engine and guess what engine that is. Yep, another Webra, a 75.

I have been thinking of selling the R90 and getting a Dyna-X. A friend just got one and you got to see the fan size on this thing.

04-24-2007 Over year old.

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Jarno
Veteran
Location: Finland

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Quote
have been thinking of selling the R90 and getting a Dyna-X. A friend just got one and you got to see the fan size on this thing.

Yep the Robbe fan (Dyna-X fan) is superior to just about anything. It will do the job great even with the Webra Hi engine. I actually have three Dyna-X models and two of them are powered by petrol Webras and they're running fine. If you're interested getting a Dyna-X PM me as I have one too many and I'm getting another Cuatro as well so I could probably sell you one it you're interested.

Cheers

04-24-2007 Over year old.

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3DPP
Senior Heliman
Location: Vienna/Austria

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Hi Jarno,
may be I know why you are took a Cuatro?

Tomorrow we are mount a 150 gas in a Cuatro

One is running to time with great success in a Nova from Claus which fly F3C like you.

BR Peter

04-24-2007 Over year old.

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sharam
Elite Veteran
Location: Northern California

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A 150 Gas! Now, that is pretty cool.

Please remember to update us!!

Thanks.

04-24-2007 Over year old.

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Jarno
Veteran
Location: Finland

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Hallo Peter,

you read my mind! Yes I'm planning to get another Cuatro and that nice 150 size gas engine would fit a Cuatro really well. Now my Cuatro has a Zenoah engine, but I like the Webra gas engine better for F3C as it's a lot lighter, smaller and revs higher. I have them on my Dyna-X and they're great. That's why why I'm planning to get another Cuatro too.

Please let us know more about this new engine Peter. I guess you have to make a new engine mount or modify the original? What gear ratio are you guys using with it?

Cheers

04-25-2007 Over year old.

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3DPP
Senior Heliman
Location: Vienna/Austria

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Hi Jarno
Hi sharam
we have in the Cuatro a 390 or 395 belt, from Webra a new Motor Mount with same high as the standard but more broad and we needed 4mm to shim.
Gear ratio to time 7.5,think it is a 27 clutch.
Motor is inside now and tomorrow my friend will have the first flights.
Some photos coming soon.

BR Peter

04-25-2007 Over year old.

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3DPP
Senior Heliman
Location: Vienna/Austria

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Here some photos

04-26-2007 Over year old.

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sharam
Elite Veteran
Location: Northern California

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Wow, great pics. What is the HP rating of this engine? Other specs?

It is now tomorrow! Did you fly it yet? THANKS!!

04-26-2007 Over year old.

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Harris
Senior Heliman
Location: Cyprus

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3DPP,

Any chance that Webra make the 91 gas engine work? It seems a bit premature to jump to a 150 when they have had so many problems with the 91.

Do you (and Webra) seriously think that there will be anyone crazy enough to buy this new engine???

04-26-2007 Over year old.

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nadman
Senior Heliman
Location: ...

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Five more flights (12 min) today

Was tempted many times to flip it inverted but just didn't have the b---s.
Average Temp is staying below 290F. The engine runs fine without the regulator as long as I stay within the min and max mentioned fuel levels.
I think you can add me to the Webra 91i success story list.

Jarno,
Can you tell me what gear ratio and head speed you have in your Dyan-X.

04-26-2007 Over year old.

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3DPP
Senior Heliman
Location: Vienna/Austria

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@sharam
He had only some minutes before the tail failed.
The crown gear didn't hold in place and was spinning, never had that before. So he had a hard auto rotation and must replace crown gear and boom.
Over the weekend we are out at a fun fly, then buying parts and repair and some tests more.
HP I don't know, also didn't ask for, what I saw looks fine, may be a pipe will be fine.

@Harris
I think the 91i work, for sure it is difficult to tune the needles, for a 30% nitro guy may be impossible, but that's not a failure.
I saw it today as my friend tried to start the engine, if the needles not right the motor don't run, we thought to hot and so on, but still nothing else as the needle setting were wrong, once set right the motor did start very well.

04-26-2007 Over year old.

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Fixit
Elite Veteran
Location: UK

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I also think Webra should recall all the 91 gas engines and give refunds because when marketing the 91 gasser they said it was a straight replacement for the nitro so they were willing to sell to nitro model owners knowing full well we wouldn’t be able to tune them. I laid out over £600 on the strength of the marketing thinking I would get a usable product.
Would I be right in saying that most of the success stories have contact with or friends that work at or with Webra?
I will say Webra helped me all they could and repaired my engines first time round but it wasn’t long before I was chasing needles all day and night trying to keep the heat down and the Heli up.
I’m now stuck with two engines and airframes I cant use and don’t know were to go from here.

04-27-2007 Over year old.

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Engines Plugs Mufflers Fuel > New 90 size gas engine from webra

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