ipoblete

hi,
Im back to heli's with my 110 and I want to ask you about V-max engine trouble that some poeople are talking about. I can't found one post that talk about the problem. Can someone explain it?
regards

Cambo

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Hi

They do not hold a tune or are mearly impossible to tune. They don't start up that fast and are near impossible to start once they have quite. The V-7 connecting rod broke on mine just last year. They quite alll the time during a flight. It was hard to get more than a 2 minute flight.
To some it all up
THEY SUCK!

Have fun
Cameron

jez33

yes they are the worst engine that ive ever had the misfortune of owning in a heli..

BTW cambo. what fuel were you using as i was trying 20 percent fuel but i had exactly the same result you mention above but then my other heli pilot mate said 'do you want to try my 30 percent' so i tried it and the engine was much much much better.
it ticked over quite reasonably (tho still not perfect) and went through the whole tank..oh and i didnt put any more compresion spacers on the head. it just has one ring..

has any one else had good or bad results on these engines with 30 percent fuel ?????

ipoblete

hi,
thank you for this reply. Any advice or solution for this engine?
regards

Cambo

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Hey Jez 33

I was actually initially running cool power 30 heli. I had been running it on my os fl 70 and figured heli fuel should work in a heli. Well i was wrong, i don't think it has castor. It blew its cam rod using that fuel. Got a new one on waranty and had better results on 15% with castor. I converted to a corona with accelent results. Let me tell you though, that is pricey.

ipoblete

I don't think there is a defenet result to fix these motors. There problem, i believe, is mostly in there horrible carb. Some people have gotten a good one. I personaly think the engine is to small in the first place for the heli. I solid size would be a .12 racing engine. If i could, i would buy an os 12 with the smallest gears you can find, convert to the corona long blades and boom. Put some 2 dot grips on and have a blast.

jez33

hi canbo...
thats quite strange about your experience with fuel as ive been using castor 20% and the engine was/is very hit and miss..my friends fuel was as i say 30% but it was a synthetic fuel n not castor...well strictly speaking i already had a half to quarter of a tank of my fuel in it and he just filled it up with his synthetic 30% fuel and for this engine the results were very much more improved..

how many compression rings do you have on the head ?? i just use one as any more make it run worse..

i totally agree with you the carbs are just too crude/simple.. i was thinking myself to put a small os10. in it but i dont know the best way to get the pinion gear on the os10 as i dont really want to adapt the os10 engine really...

Cambo

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Hi jez 33

I gave up on that engine and converted to electric with great results. I get almost 15 minute flights.
Let me tell you though, as mush as i like electrics, there prices really turn you down.

This is my thoughts on that carb
I think there carb should be fitted with a slide carb. Being able to control the carburator will make it run much better. Ever wonder why every manufacturer out there has either a slide or rotory carb on the car, plane, and heli engines. I mean light machines should ask themselves this. Does it make sence for you to open and close the exshaut to control engine rpm when the exshaust lets the engine breath.

jez33

yes i am thinking also as electric as a possibility too..i think they use the throttle exhaust vaulve because its cheaper and simpler !

do you think any of the small rc car engines will fit as they have the carb type throttle and look roughly the same size ????

Cambo

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Hey Jez 33

It had been done, i even looked into it myself. The difficult part will be finding gears that will work. My Rc car gears, for example, would skip 1-2 times on the main gear. It will also have to be geared very, very high. The crutch will also have to be modified. You could try contacting ballistectechnoligies and see if they will custon make a crutch/gears for the engine you would pick out. They usually deal with Corona upgrades so you will have to e-mail them.

Good Luck

AndyW

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Guys,

I'm sorry you're all having trouble with your LM engines. Once broken in, I have found them to be outstanding. Easy to start, excellent top end, excellent and reliable idle and excellent transition.

Have a look here.

http://www.youtube.com/profile_videos?user=hopeso

The engine was converted to rear exhaust and a special muffler/throttle was built. Notice that it idles solid and reliable and the pickup is almost instant,,,, if you can ignore the audio lag,,, not my fault, it's YouTube's fault. This modified engine is going into an ARK400 that is being converted from electric, to glow.

So if any of your engines need a home, maybe I can help.

jez33

hi..
yes i did get it to run reasonably in the end,,,it seems to be the fuel thats quite criticle..

did your engine work ok in a heli too btw as i dont think just putting a prop on it will compare as well as on a heli !!!

AndyW

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Jez,

I have found that the Norvels are actually NOT critical to fuel. I've used all manner of fuels in my LiteMachines heli with no problems. But I broke that engine in on a prop. The Norvels WERE set up very tight so that the abrasive, anodized liner would actually, kind of hone down the piston to a perfect running fit. The crucial part of starting and breaking in a Norvel Revlite engine, whether in the heli or with a prop, is to first heat up the cylinder as hot as you can get it with a heat gun. Then it turns over easily for a start. Then, as the engine wears in, the fit gets better and better.

But even after that, the other important element is to NOT overprime. We all have been accustomed to slobbering the prime to small engines because they would tolerate that kind of abuse and because, very often, that's the only way they would start by hand. Back then, micro starters were not available.

The issue is the anodized cylinder. Anodize is a form of aluminum oxide. Where have you heard of that? Well, aluminum oxide is used on SANDPAPER. Yep, it's very abrasive. BUT, the aluminum oxide layer has a honeycomb structure. As such, the pores actually hold oil, becomes slippery and makes the compression seal very good,, better than any other system, really.

The problem arises when you overprime. All that raw fuel tends to wash out the oil from the pores and now you have a cylinder that'll snag the piston UNLESS it's turned over very fast. BUT, when you do THAT, remember the overprime? Because of the good compression seal, and the extra fuel in the engine, you can too easily get hydraulic lock and applying even a micro starter, you can jam up the engine and bend a rod. Then, the piston bangs against the bottom cover and the rod eventually breaks. You can break cranks this way too.

And BTW, the latest batch of engines and piston/cylinders have eliminated the tight fit. They are now set quite loose so all the old problems have gone away.

Plus, LM is having a half price sale on both the 6 and the 7 engine.

And about fuel, I run Cool Power 25% in mine, for heli AND airplanes with no problems. Another issue is that if you use a fuelling bulb, the rubber compound dissolves in the fuel and fouls your glow plug. And the rubber in a plunger type fueller can also do the bad thing too. I've never used either and have never had a problem.

jez33

hi again,,
thanks for the reply..
ive never really had a novel from brand new as the 1st engine came with the heli 2nd hand (which ran qite well for a small engine ) so i havnt needed to run one in..the replacment engine i got for it was also 2nd hand but it has good compresion..it was a slighty bigger engine too..
the strange thing is that the fuel i used for the 1st heli engine worked very nicely with that but then with the 2nd engine i found it was hard to keep the engine running once started which made me reluctant to fly to high incase the engine would stop..but when i tried the 30% fuel in the 2nd engine we knowticed how much more the engine liked it and it used the whole tank of fuel each time..
so when i say i think fuel is criticle i mean more the nitro content rather then the fuel oil type ect...

ive not realy had a problem as such to start the engine as i find for me at least the easiest way and most efective is to use and electric start on it without priming,but as the engine is being turned i very briefly put my finger over the air intake so i can get it started from hot or cold in seconds..(i dont recomend that mehtod to all pilots but me n you have had a few years experience with engines to know when we should take the finger off ofcause )..
i might have a look at the new engines perhaps..i run my engines in most of the time with a prop too,just depends if i ca be nothered to do it on a test bed,else ofcause id do it in the heli but as you sugest it might be better to run it in with a prop..

i think cambo and i ofcause are mostly comparing these engines with other engines of its size because there are other engines of the same size that dont need such ataintion/hastle to get to run well.

Cambo

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AndyW

Is that the same engine that came with the LM heli.
I have been interested in putting a prop on this thing and seening if i get a performance increase.
I am wondering what size prop you use?

AndyW

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Cambo,

Yes, that IS a LiteMachines engine. I did an article in Flying Models in August of 2001 on using the LM engines with custom made, exhaust throttles. Lots of R&D showed that LM got it exactly right. BUT, the throttling MUST be done behind the muffler and not ahead of it.

See this for more infromation,

http://www.rcuniverse.com/forum/m_25...tm.htm#2544245


The Norvel engines CAN throttle perfectly and give excellent power. They just need to be Big Migs (same as LM) and must have an adjustable airbleed added to the OLD style, intake throttles. The new style CAN be made to work but it's hit and miss.

The prop I use on most of my 1/2As are the Grish, black Tornado props, 6 X 3. APCs in this size are a bit light and Cox's work well too but they do load the engine more and in some planes, this not good. The Grish are between the APC and the Cox so they do a good job for the average application.

Cambo

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can the lite machines muffler be simply reversed, this would put it behind the engine.
Since mine heli is electric now i would like to do something with this engine, maybe put it in a small plane.
Could i like make a profile for this thing to run on. That would be so cool!