MVVS .49 or Rossi .45 or Irvine .53 or Webra .50  
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All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> Glow Engines >> MVVS .49 or Rossi .45 or Irvine .53 or Webra .50
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MVVS .49 or Rossi .45 or Irvine .53 or Webra .50 - 8/3/2003 8:05:54 AM   
Woody 51



Posts: 1159
Joined: 6/21/2003
From: GeelongVictoria, AUSTRALIA
Status: offline 		Some interesting comments in this thread. I have learnt a few things.

But in exploring a few of the comments I came across "The Bolly Book" website on the net.

It is written by Les Bolenhagen, of Bolly Props fame.

Les has been involved in both aeromodelling and also sport (ultra light) aviation for some time and this quote is cut and pasted from his book.

I put it here to share with all.

On Nitro:

.."Nitro is a power enhancer as it increases the amount of oxygen available in the fuel for combustion. The down side is that it generates more heat (often needs a lower combustion ratio) and can contribute to rusting of the engine (caused by the acidic by-products of the combustion). The use of small amounts of nitro will help most engine run smoother.

Nitro methane will NOT increase rpm, but as it’s combustion produces more energy, the engine will develop more torque, allowing the use of bigger propellers, or better operation under high loads. A classic example of this is R/C aerobatics where adding nitro to the fuel will give a big performance increase in vertical climbs..."

Check the rest out at:

http://www.bolly.com.au/book/

(in reply to davidl340)
       Post #: 51

MVVS .49 or Rossi .45 or Irvine .53 or Webra .50 - 8/3/2003 8:12:09 AM   
GuamJan


 

Posts: 10
Joined: 6/13/2003
From: TamuningGU, GUAM (USA)
Status: offline 		You guys are great...thks in advance.

Ok, are there any other engs in the .49-.53 area that come with a tuned muffler and are in the $150 price range?

Would the cheap engs like the GMS, Tiger Shark, etc with a tuned exhaust be as powerful as the MVVS or Webra. I know not all have an eng in that size bracket. I guess my question is, given the same muffler, is there really a difference?

(in reply to davidl340)
       Post #: 52

MVVS .49 or Rossi .45 or Irvine .53 or Webra .50 - 8/3/2003 8:15:07 AM   
bgi



Posts: 907
Joined: 2/19/2002
From: Duluth, GA, USA
Status: offline 		More energy and no increase in RPM? Say, wha?????

(in reply to davidl340)
       Post #: 53

MVVS .49 or Rossi .45 or Irvine .53 or Webra .50 - 8/3/2003 8:20:07 AM   
bgi



Posts: 907
Joined: 2/19/2002
From: Duluth, GA, USA
Status: offline 		[QUOTE]Originally posted by GuamJan
Would the cheap engs like the GMS, Tiger Shark, etc with a tuned exhaust be as powerful as the MVVS or Webra.[/QUOTE]

Maybe, but...

Full-size tuned pipes are very "peaky" with a lot of power in a narrow RPM range but comparatively weak at the non-optimized RPMs. Great for racing, but not the ideal setup for hovering and other 3D manouvers where you need something to happen instantly when you hit the throttle.

My Webra 50 w/12.25x3.75 APC will hover my Knife ARF at 1/4-1/3 throttle. Each click of throttle makes a difference. On a tuned pipe, you'll be jumping on and off the pipe, making the throttle management quite different.

I wouldn't want to fight a tuned pipe while trying to hover. They're also VERY LOUD.

(in reply to davidl340)
       Post #: 54

yup - 8/3/2003 9:18:32 AM   
Razor-RCU



Posts: 5294
Joined: 3/21/2002
From: Ramona, CA, USA
Status: offline 		That last post says it all-

I have never had a GMS or Tigershark engine but.... Do a search on each engine on here and that will show you a great number of folks with each engine, and what they are experiencing-

For example the Irvine-53 and TT Pro-46 have a huge number of positive comments on here- Same with MVVS-49 Webra-50 and YS-45...

I think that says it all- cuz' there is gonna be somebody that says the GMS (as an example) is the finest engine anywhere, and someone else who says its a paper weight- Go by overall opinions and it helps a great deal-

I am on a budget but I will not buy cheap engines....


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(in reply to davidl340)
       Post #: 55

Webra and MVVS - 8/3/2003 10:03:54 AM   
DarZeelon



Posts: 7343
Joined: 4/9/2003
From: Rosh-Ha'Ayin, ISRAEL
Status: offline 		GuamJan, bgi,

The Webra excels at higher RPM, with its high volume muffler, which is not tuned, as far as I know.

The MVVS .49 spins heavy props at RPM levels that you are probably used to seeing with .60 engines.

The MA 11x6 prop is spun at about 14,600 RPM, which is close to the top the tuned muffler's range and it would unload very little in flight. I would not recommend this prop with the tuned silencer.

If you want to use MA, go with an 11x7 minimum.

An APC 11x6 offers more load. An 11x7, 12x6, 12x7, 13x4 are among the good sizes.

If you want a 10" prop, an APC 10x8 would be the absolute minimum, to keep it around 14K.

All this is achieved with cheap, 0-5% nitro fuel.

If you try a 10x6, it will resemble "full throttle in neutral gear". Wrong prop.

A Webra will spin a 10x6 at over 15K, however.

For the MVVS to run on 15% nitro, you will likely need two head shims. Can't you mix your own fuel with 5% nitro, in Guam?
It would be preferable to modifying your engine.

The MVVS would show 150-200 more RPM, if "shimmed" and run on 15%, than it would unaltered, on 5% nitro.

It would run better (idle, response) if used as it was originally engineered and designed.

< Message edited by DarZeelon -- Aug 6 2003 1:14PM >

_____________________________

Dar Zeelon - ISRAEL - ddzeelon@gmail.com
MVVS - Jett - Nelson - Bolly - Mejzlik

(in reply to davidl340)
       Post #: 56

MVVS .49 or Rossi .45 or Irvine .53 or Webra .50 - 8/3/2003 2:21:53 PM   
sport10


 

Posts: 715
Joined: 12/31/2001
From: Loxley, AL, USA
Status: offline 		I would also like to commit that the Webra is also just at home lugging the large props too. When I was using the 12.25x3.75 APC which is quite a load this engine spun it at 13000 to 13200 on 15% Omega Fuel. This was with great throttle response too on a somewhat heavy prop. I have since gone to a 12x4 APC which it spins around 14K. This is with super fast throttle response and no apparent loss in thrust. Great combo for my Topcap.

Both the MVVS 49 and Webra 50GT are great engines. It all boils down to pick the engine that best suits your needs. If you live in an area where it will be hard getting 5% or FAI. Then the MVVS does not make much since to buy in the above situation above. I personally do not believe in having to modify a new engine to live on fuel it was not designed for. I am lucky to have a hobbyshop that stocks quite a varity of fuels and will more than likely try the MVVS 49 next time I need a new engine of this size since I already have a Webra 50.

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(in reply to davidl340)
       Post #: 57

MVVS .49 or Rossi .45 or Irvine .53 or Webra .50 - 8/3/2003 7:34:52 PM   
adrian-RCU



Posts: 1686
Joined: 10/27/2002
From: tel avivna, ISRAEL
Status: offline 		just for interest the webra is abn and the mvvs and rossi abc, both the latter will out last the webra for sure.

(in reply to davidl340)
       Post #: 58

No - 8/3/2003 7:49:44 PM   
Hobbsy



Posts: 10938
Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: offline 		There is no reason why the MVVS and the Rossi would outlast the Webra.

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"I have gone faster backwards, upside down and on fire than most people have gone at all" Don Garlits

(in reply to davidl340)
       Post #: 59

MVVS .49 or Rossi .45 or Irvine .53 or Webra .50 - 8/3/2003 8:09:04 PM   
adrian-RCU



Posts: 1686
Joined: 10/27/2002
From: tel avivna, ISRAEL
Status: offline 		yep = first hand experience

(in reply to davidl340)
       Post #: 60

Re: Webra and MVVS - 8/3/2003 8:50:11 PM   
bgi



Posts: 907
Joined: 2/19/2002
From: Duluth, GA, USA
Status: offline 		[QUOTE]Originally posted by DarZeelon
GuamJan, bgi,

The Webra excels at higher RPM, with its high volume muffler, which is not tuned, as far as I know.
[/QUOTE]

The literature claims the Webra exhaust is "semi-tuned."

Thanks for all the scoop, Dar.

(in reply to davidl340)
       Post #: 61

MVVS .49 or Rossi .45 or Irvine .53 or Webra .50 - 8/3/2003 11:13:16 PM   
RaceCity



Posts: 1842
Joined: 7/10/2002
From: NotUpNorth, USA
Status: offline 		Anyone else care to weigh in on the issue?

Sorry to be a pain in the keester....

But PLEASE close this thread out....it's not even productive anymore.

Dave. You started with three GOOD choices in engines. You wouldn't be disappointed with any of them....you now have 60 opinions to sort through. I hope you weren't confused before, because now you CERTAINLY are.

Buy a motor...let us all know how things work out.

'Race

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AMA 63990

(in reply to davidl340)
       Post #: 62

Semi tuned?! - 8/4/2003 12:08:13 AM   
DarZeelon



Posts: 7343
Joined: 4/9/2003
From: Rosh-Ha'Ayin, ISRAEL
Status: offline 		Bgi,

A tuned exhaust system utilizes lengths and sound waves to create a supercharging effect.

The Webra exhaust is optimized for volume and shape, to minimize the back-pressure encountered by the exhaust gasses, exiting the cylinder, simulating an open-exhaust situation.

I would hardly call this arrangement a truely tuned exhaust.

The Webra is a good, light engine. Too bad they fell to the nickel bug. The previous chromium, ABC engines lasted for years.

_____________________________

Dar Zeelon - ISRAEL - ddzeelon@gmail.com
MVVS - Jett - Nelson - Bolly - Mejzlik

(in reply to davidl340)
       Post #: 63

Re: Semi tuned?! - 8/4/2003 3:06:47 AM   
bgi



Posts: 907
Joined: 2/19/2002
From: Duluth, GA, USA
Status: offline 		[QUOTE]Originally posted by DarZeelon
Bgi,
A tuned exhaust system utilizes lengths and sound waves to create a supercharging effect.
[/QUOTE]
Yup.
[QUOTE]
The Webra exhaust is optimized for volume and shape, to minimize the back-pressure encountered by the exhaust gasses, exiting the cylinder, simulating an open-exhaust situation.

I would hardly call this arrangement a truely tuned exhaust.
[/QUOTE]
Ok. Let's gripe to Horizon and see what they say.
[QUOTE]
The Webra is a good, light engine. Too bad they fell to the nickel bug. The previous chromium, ABC engines lasted for years. [/QUOTE]
Bummer. How many gallons do you think they're good for?

(in reply to davidl340)
       Post #: 64

MVVS .49 or Rossi .45 or Irvine .53 or Webra .50 - 8/4/2003 3:48:11 AM   
davidl340


 

Posts: 30
Joined: 2/6/2002
From: Gulfport, MS, USA
Status: offline 		I ordered the MVVS .49. Purchased 2 gallons of 5% omega and some castor oil for break in. Thanks Dar. Sorry for not responding earlier. My internet is down, so now i'm having to write this on my PDA phone! PIA! I'll let you all know how it all goes.

(in reply to davidl340)
       Post #: 65

MVVS .49 or Rossi .45 or Irvine .53 or Webra .50 - 8/4/2003 4:26:35 AM   
RaceCity