Webra 91 P-5 motor issue in Robbe Nova Cuatro

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Home › ✈️Aircraft › 🚁Helicopter › Helicopter Main Discussion › Webra 91 P-5 motor issue in Robbe Nova Cuatro

07-24-2020 06:48 AM 12 days ago

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0Post 1

Hendry Hellerle

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Gauteng, South Africa

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Webra 91 P-5 motor issue in Robbe Nova Cuatro

This Robbe Nova Cuatro has been in storage for 11 years! I serviced EVERYTHING on this heli, and must say despite its years its still an absolutely beautiful machine!
The Webra motor I'd like to keep because of its historical value. Needless to say the bearings had it, as the ring was stuck inside the piston. I replaced the bearings, and managed to free the ring. Unfortunately the rind bended a bit. I worked on it for a few days to get it as perfect as possible and reassembled everything.
This old motor idles beautifully, and is very responsive, but it has one gremlin I cannot get rid of.
The motor keeps high operating RPM for a few seconds, and dies instantly all of a sudden. Tuning the low and high needle has got little to no effect on this problem. I'm running it with OS no 8 glow....
Please help me to save this piece of Austrian history. I've added a YouTube link that demonstrates the issue at hand.

Video:

Watch at YouTube

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07-24-2020 07:02 AM 12 days ago

0Post 2

TMoore

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Cookeville, TN

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Put blades on it dude. It's meant to be loaded up.Part 107.
The only ZERO flight hour certificate in the world.
It's like getting a driver's license without the driver's test.

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07-24-2020 07:54 AM 12 days ago

0Post 3

Rojoalfa

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Punta de Mata, Monagas-Venezuela

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/
/

Yes... Don't accelerate your motor without blades... It needs a load to work properly.

Ok...
Did you check silicon tubing layout?
Every fitting is in place and not clogged ?

/Saludos cordiales,

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07-24-2020 02:13 PM 12 days ago

0Post 4

wjvail

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Meridian, Mississippi

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How old is your fuel and has it been stored tightly capped? If fuel has been properly stored will last 20 or more years. Fuel that has been stored such that it isn't airtight it will absorb moisture. Moisture in your fuel will do what you are seeing. I tell everyone that is having engine trouble: "Try a new OS #8 plug and fresh fuel."

Another question... This may be impolite but your equipment looks pretty old. That in itself isn't a problem but if it hasn't been stored well there is a possibility the ring is stuck or there are issues with the fuel lines and or filters. Are they healthy? Have you looked inside the tank and checked the clunk line?

Does your fuel foam as it spools up? It looks like your tanks is pretty empty and vibration may be causing the fuel to foam causing it to go lean. It looks like you are using a header tank. Is it full?

Your model should spool up without the blades. I've done it many time over the years. Just be careful. It will overspeed if you let it.

Keep us posted. I like a good mystery."Well, nothing bad can happen now."

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07-24-2020 03:03 PM 12 days ago

0Post 5

JLF92677

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Southern California

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How old is the fuel you are using?

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07-24-2020 03:22 PM 12 days ago

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JLF92677

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Southern California

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Sorry to have posted the same question as wjvail, I watched the video and responded without reading the rest of the posts. I do think that most likely the problem is old “wet” fuel.

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07-24-2020 11:28 PM 11 days ago

0Post 7

wjvail

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Meridian, Mississippi

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JLF92677 How old is the fuel you are using?

Great minds think alike

."Well, nothing bad can happen now."

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07-24-2020 11:53 PM 11 days ago

0Post 8

JLF92677

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Southern California

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It's funny how we both had the same initial response. This exact thing happened to me back in the mid 90's. I had been away from the hobby for a few years, so when I returned to the hobby, I used a half empty old metal can of fuel to start an airplane engine. Engine started and idled just fine with no issues, but once I raised the RPMs it flamed out. I could not figure out what was causing it. So I tried a number of things and wasted a bunch of time before I reached out for a new can of fuel. BINGO, all else was fine. Back then we did not have forums like RunRyder to ask questions and get answers... it was trial and error back then. GREAT to have the internet and RunRyder around these days!!!

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07-25-2020 02:58 PM 11 days ago

0Post 9

douflytoo

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Valparaiso, IN. USA

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Also, check out post #30 from this thread, is specific to Webras, may help in tuning.
https://rc.runryder.com/t80175p2/

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08-02-2020 02:12 PM 3 days ago

0Post 10

wjvail