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Gasser Model RC Helicopters > Webra 91 P5 Hi, Nitro conversion
 
 
Brunobl
Veteran
Location: Pomerode, SC, Brazil - 26 40S 49 11W

Hey Fixit,

From your conversion I must assume this Webra ended up not doing well in its intended (gas) configuration?

It would be a shame. I recall some time ago reading about this standard crankcase, 90-size, gasser engine and thinking it could be a killer combination with many 60 and 90-class helis.

Then the news started coming (this forum included) that the engine had overheating, inconsistent running and flame-out problems. The last I heard, Webra was looking into those issues but users weren't too happy with the company's engine-return policy.

I guess your decision to finally convert the engine to nitro points to the closing chapter on this interesting engine. That's too bad. A bit more competition in the engine field would be healthy for the gasser side of the hobby. Not only that, but a drop-in gas alternative for nitro engines (specially if the RPM range were comparable to nitro so users didn't have to fuss with gear ratios) would have been more than welcome.

It will be interesting to see if there is anything new coming.

EDIT: Congratulations on your conversion success. It must have taken more than a few hours of thought, planning & tinkering. Well done!

-------------------
Best regards,
Bruno.
01-20-2008 05:02 AM
 
 
Fixit
Key Veteran
Location: UK

Hi Brunodl

The last thing I wanted to do was go back to nitro believe me but after spending months trying these engines in 4 diferant airframes it became very clear these engines weren’t fit for the use they were marketed for and that was a gas replacement for the 90 Heli.
I know webra are now selling a bigger version of the gas engine but by all accounts it’s having the same problems. How do they get away with this?
Funny but some guys in Austria claim to have the 91 running well, after doing rework on the porting but how many owners in this hobby can do that.

If I had bought these engines in the UK the seller would have been forced to give me my money back but instead I bought from CyberHeli ( big mistake) when I contacted them they say they don’t offer warranty on webra engines webra honour it themselves so you have to ship it back at your own cost for webra basicly to try and repair an engine that’s unfit for sale in the first place.
They mend it send it back and then the cycle starts all over again, they wont start unless you spend hours messing then when they do they fall apart.

I’m no expert but I have built at least 15 helis both nitro and gas and never had a problem getting the engines to run, I gave the webra 91 Hi engines more than a fair trial before I admitted a very costly defete.

One of the engines I bought is in my Heli graveyard and the other is now running on nitro instead of being a converted nitro engine trying to run on gas.
01-20-2008 05:54 PM
HOMEPAGE  
 
 
Brunobl
Veteran
Location: Pomerode, SC, Brazil - 26 40S 49 11W

Sorry for your costly experience.
But see it from the positive side. Think of what you've learned from it (both technically and in dealing with distributors & manufacturers).

You had the guts to experiment with something totally new, that only a small percentage of hobbyists ventured into. It is far easier to go along with the crowd, but you showed you'd rather be on the leading edge, experiment and try new ideas in this hobby. Please don't let the mishap change this in you.

And...
Keep flying!

-------------------
Best regards,
Bruno.
01-20-2008 06:44 PM
 
 
Fixit
Key Veteran
Location: UK

I crashed the 600/Webra 90 on it's third flight because I hadn’t noticed the new swash plate that comes with the kit binds on the washout pins if you set it up for +/-14 It ended up striping the elevator servo gears causing me to crash

Well it needed some new blades among other bits and I couldn’t run to a new set of blades right now but I had a spare set of Sab 680mm and lots of bent booms lying around so I’ve just stretched the boom and shaft 125mm, lengthened the supports and borrowed a few bits of my 600e and fit the 680 blades on it. I guess this solution has been staring me in the face for a week and I just didn’t see it until now
02-05-2008 05:50 PM
HOMEPAGE  
 
 
nadman
Heliman
Location: ...

Hi Fixit,

sorry to hear about your crash.
I bought a C-spec head for my 91i. Hope to get my 600 airborne soon. I'll make sure I stay below 14 degrees
02-06-2008 10:08 AM
 
 
Fixit
Key Veteran
Location: UK

Hi nadman,
The new swash is deeper and bottoms out on the washout pins, I still have +/-14 by adjusting the swash mix to 45 just wish I had spotted it the first time round.

If you have the head already you will have found out you have to remove the lip on the head face, I used a grinder and a file but a milling machine would be better, I have the mixture needle at 5 to the hour, the Mid closed and the Main out 1 ¼ on 30%.
Good luck
02-06-2008 11:44 AM
HOMEPAGE  
 
 
nadman
Heliman
Location: ...

Yes, I see what you mean. The lip has to be removed. Unfortunately my hobby lathe jaws are not large enough. Will have to take it to my friends shop. More delays
02-06-2008 01:13 PM
 
 
Fixit
Key Veteran
Location: UK

Hi nadman, Sorry about that but I did mention it in an earlier post, [quote]I used the OS 91 Max SX head and OS 60K carb, the head just needs the lower skirt removing (easy job) then use the sleeve from the webra carb on the OS 60 K and that’s it but don’t forget I've still to fly it before I can tell you what it performs like.
02-06-2008 04:03 PM
HOMEPAGE  
 
 
nadman
Heliman
Location: ...

No problem.
My friend is the Webra dealer here in Tehran so I called him and he sent me a 91 glow head from one of his new engines. Installation was very easy since it was identical to 91i head. Didn't have to do or change any thing.
The engine started right up with the original 91i carb. I let it run at idle for about a tank. Tomorrow I will put the blades on and try to hover it.
02-08-2008 03:59 PM
 
 
Fixit
Key Veteran
Location: UK

Hi nadman.
The main reason I used the OS carb was because it's designed for glow fuel, you will need to watch the O rings very closely just in case the glow affects them.
Still waiting for some good weather so I can get mine back in the air.
02-08-2008 06:50 PM
HOMEPAGE  
 
 
jackheli
Elite Veteran
Location: Vancouver - Canada

Quote 
users weren't too happy with the company's engine-return policy.

Quote 
I bought from CyberHeli ( big mistake) when I contacted them they say they don’t offer warranty on webra engines webra honour it themselves so you have to ship it back at your own cost

Congratulations on you success. It is great to see that somebody managed to overcome the Webra syndrome.

I must say I went through the same grief with Webra with a 52AAR which didn't work well from day one. The main needle ended up being ejected in mid flight and when I finally managed to get a replacement the control rod broke.

Webra would not want to hear about the issue unless I shipped the busted engine at my expense. I was advised not to send it over since it would be a waste of time and money: Webra always says it is your fault.

Cyberheli didn't even answer my emails at the end...

Well done and I hope your Fixitwebra brings you lots of joy.



Anyone who has never made a mistake has never tried anything new - Albert Einstein
02-08-2008 06:53 PM
 
 
Chopper Man100
Veteran
Location: albany N.Y.

Just to add to the comments, I no longer deal with webra engines or Cyber Heli for all the same reasons mentioned above. I sent an engine back to webra and some how it was lost and never got it back. I sent it back for warrenty work. That was 4 years ago.
02-09-2008 03:29 AM
 
 
nadman
Heliman
Location: ...

Fixit,
I didn’t want to invest any more time/money on the Webra 91i before further testing it, which I just did in the backyard. For the first time the engine went through a full tank of fuel (glow). Needles had to be readjusted further. It has so much power on Trex600 that for hover, throttle was about may be less than 30 %. At current needle setting the idle is not reliable any more, but that is not a problem since at hover rpm it runs and sounds perfect (180-190F). I guess this proves my point that this carb is more suitable for glow engine rather than gas.
Thanks for the glow conversion idea for this engine.
02-09-2008 09:09 AM
 
 
nivlek
rrProfessor
Location: Norfolk England

Quote 
At current needle setting the idle is not reliable any more, but that is not a problem since at hover rpm it runs and sounds perfect (180-190F). I guess this proves my point that this carb is more suitable for glow engine rather than gas.

If the mixture is right at the hover point , but won't allow the engine to tick over reliably , I would have said the opposite is more likely to be true !

At the end of the day , it gets dark .
02-09-2008 09:33 AM
 
 
Fixit
Key Veteran
Location: UK

Chopper Man100
I can’t understand why Webra are still in business to be honest I’ve heard so many story’s about them.

nadman
Fortunately for me I had a few redundant C specs engines in my workshop so it was just an idea I had to try with the os carb the webra 91 idles perfect and in flight I’m using a full throttle curve, I’m wondering once this engine has run in on glow if it might then run on gas then only trouble there is both the Webra throttle arms on mine fell apart.
02-09-2008 10:17 AM
HOMEPAGE  
 
 
nadman
Heliman
Location: ...

nivlek,
Don’t know how familiar you are with Ultramix carb but even the glow version is very difficult to adjust since the low needle controls flow from idle till about 80% throttle. On my Webra 75 and 55 I had to scarify good idle so to have good mid-high setting. Now to take this carb and put it in a gas engine is just insane.

Fixit,
Don’t know about you but when I remember the time I spent trying to adjust the needles, the over heating issue and the ignition system reliability the answer would be never. I will stick to Zenoah. I love flying my Cuatro and it took me less than 5 minutes to adjust the needles and have not touched them since.
02-09-2008 11:16 AM
 
 
Fixit
Key Veteran
Location: UK

[quote]the answer would be never
Yes I guess your right, I would be asking for a miracle and Webra don’t do those
02-09-2008 11:31 AM
HOMEPAGE  
 
 
nivlek
rrProfessor
Location: Norfolk England

I had no such problem with my Webra 75 or West 50 , personally I don't find them difficult to adjust at all , different to an OS carb , but not difficult
I assume that the needles fitted to the petrol carb will be different due to the different viscosity of the fuel and the different fuel/air requirements .

At the end of the day , it gets dark .
02-09-2008 02:07 PM
 
 
Fixit
Key Veteran
Location: UK

Quote 
I assume that the needles fitted to the petrol carb will be different due to the different viscosity of the fuel and the different fuel/air requirements .


I doubt Webra would have thought about that, I think they just added E-ignition to a 91 glow engine.
04-19-2008 12:41 AM
HOMEPAGE  
 
 
Billme
Key Veteran
Location: MS

I sure would have like to tried Webra...When you change to ignition, and running gas, you need to get the engine configured for the hotter temps...They have the same liner as a gasser..( the liner is not removable, its part of the cast), so they new it was going to be more heat...
Larger head fins would have been good...

Configuring the heli would be different...Since the 91 on ignition with gas would run slower, because it is producing more torque, so it needs a more efficient fan design to run at 11 to 14 grand, instead of 18 grand, on most helis this engine was tried on..Not to mention optimizing the cooling shroud and engine clutch, and gear ratio..
If anyone still has one, I have a few things I might could trade or just buy out right to try some of my ideas..Would be glad to hear from someone..
Regards,
Bill
04-19-2008 01:25 AM
 
 
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Gasser Model RC Helicopters > Webra 91 P5 Hi, Nitro conversion
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