rmh

Old wives tale---
tuned pipes do not shove unburnt gasses back into the engine -this is a false understanding of tuned systems - the story spreads like an Urban Myth.
look at logic
why would you want exhaust back in the chamber?
what does happen:
the rapidly moving exhaust expands down a long pipe - then slows up
this "slowing up"creates a pressure wave BACK toward the engine.

as the rapidly outbound gasses flow --they help suck in MORE fuel air mix than would have happened - if the exhaust had not flowed out of the combuston chamber, so completely. The "shove back" you mentioned is more like a instant shock wave which prevents the incoming fuel mix from flowing into the exhaust pipe. It is in effect , an invisible valve

so :
the pipe pulls in more fuel mix
that is where the power come from

Making more power does make more heat because power is heat ( no cold power)

Kema

Have anyone tried this set?
http://www.adaracing.com/viewitem.ph...aincat=scooter

Cant find a dealer from europe and ada-racing uk is down.

Some air filtering would be nice cause engine is installed inverted.

Charley

My Feedback: (2)

I can't count the number of times I've told people this. They just don't want to hear it. ;^)

CR

jamiem75

My Feedback: (2)

MR. HANSON,
THAT MAKES A LITTLE MORE SENSE THAN THE EXPLANATION I WAS GIVEN INITIALLY.
THANKS,
JAMES

pe reivers

edit:
miised a few posts. Answer not needed any more.

pe reivers

The carb extension will fit, but the air filter will not clear the prop without a prop extension.

clm

My Feedback: (24)

Does the MVVS tuned pipe need to be tuned if using MVVS header #3265 or is this combination already the correct length for best performance?
When should I tune the pipe (right away or after engine run-in)?
What is the proper sequence for run-in and tuning of a pipe for 1.6?

My guess at the correct sequence:
1. Mount engine, pipe and 18-6 prop. MVVS 1.6 with MVVS header #3265 and MVVS tuned pipe #3266.
2. use Mobil T2 oil @ 25-32:1
3. carb setting L=1:50 H=1:35
4. run engine for approx 2 gallons @ this rich oil and carb setting
5. tune carb low and high needles for best performance
6. tune pipe by cutting 1/4" of header at a time till RPM stops increasing
7. re-tune carb low and high needles for best performance
8. enjoy high performance of light engine


Tks
clm

pe reivers

1. Mount engine, pipe and 18-6 prop. MVVS 1.6 with MVVS header #3265 and MVVS tuned pipe #3266.
2. use Mobil T2 oil @ 25-32:1 (or other fully synthetic two stroke RACING OIL)
2a Take care of good engine cooling (cowl in/outlet, baffling, guide plates)
3. carb setting L=1:50 H=1:35
5. tune carb low and high needles for best performance, but rich about 100 rpm
4. run engine for approx 2 gallons @ this rich oil and carb setting
4a, after run-in, keep mixture at 3% oil
6. not needed: Pipe is tuned to engine for up to 9500 rpm
7. not needed
8. enjoy high performance of light engine

devcon9

I plan to go the 'tuned pipe set up' any recommended CF pipes on par with the MVVS 3266 pipe..? Just trying to keep everything as light as possible.

Thanks


Good Flying
Tony

rmh

Cutting the pipe/header for peak power is not a good idea for typical aerobatic flying
Rather it will cause serious performance problems as the engine cools/ heats during the throttle variations durina a flight
Most tuned pipe tuning info is of little value for our non racing setups
I could bore you to tears with what happens during the change up from low (idle power --to full power
but suffice to say - leave the pipe alone - and DO NOT add a larger prop load .

pe reivers

The extra price is better spent on a very light header. The mvvs pipe is quite light and very good.
MTW (My pages) offer standard Stainless steel headers with either 50mm or 90 mm offset from the flange. For the adept braze-soldering guys there are kits from simple, to swan neck constructions.

agbjarn

I wonder if the MVVS 160 is too big for a 54" wingspan Ultimate biplane (as the Goldberg Ultimate 10-300 ARF http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXDJE1 ).

This model is intended for a .60-.90 two stroke or .90-1.20 four stroke glow engine. At least one has used a Saito 1.80 four stroke ( http://www.rcdon.com/html/the_ultimate_project.html ).

(I am using the MVVS-160 + tuned pipe in my Protech Kanata S180).

Agust

bl3ck

My Feedback: (6)

I just purchased the tuned pipe( MVVS header #3265 and MVVS tuned pipe #3266) for 1.6 and need to know what distance the header should be from the pipe inside the coupling? They should provide some directions with these pipes, anything would be nice. But then again maybe they think if you are going to use a pipe you should know what your doing.

pe reivers

They do provide directions.
The header should not touch the pipe, so 1/4"clearance is OK. This dimension is not very critical, and not rocket science. Just don't make it 1", which is stretching it, and exposes the coupler to the hot gasses too much.

bl3ck

My Feedback: (6)

I must have been the lucky one that didnt receive directions. Oh well, i learn more from these forums anyway. Thanks for your help and quick response.

devcon9

I am now going the tuned pipe (3266) route, header yet un-decided,
Chosen model is the SebArt Funtana S140, I am contemplating mounting the MVVS using rubber mounts, any pro’s and cons of using this method.

Thanks
Good flying
Tony

rmh

yeh - don't
I have run the piped engine, in a Funtana and a Showtime - solid mounted on the plasic kit mounts
smooth running and they got flown a lot
also letting it shake at idle like a friggen YS will simply wreck the header connection (as it does on many of the "pattern" things.
The best method of controlling vibes is proper mass balancing -that is -- the mass atached to the engine contributes to stability
Some fuselages are worse than a cheap violin at controlling harmonics.

devcon9

Thanks Dick, for the info and pic, think I will go with the plastic mounts.
Good flying
Tony

jamiem75

My Feedback: (2)

My coupler for my tuned pipe failed today. It was the stock coupler and I think it's just silicone. I read in here or onanother thread that there is a better one available. Any suggestions?

I am flyin it in an ultra r/c giles with the skorepa props that Mr. Hanson suggested and it made a heck of a difference. It felt like it produced quite a bit more thrust and the spool-up was definitely faster.

When the coupler failed, there was, obviously, a difference in sound and it felt like there was a substantial difference in power. Made a believer out of me on the tuned pipe.
Lots of good stuff in these threads. Thanks!

rmh

Note the above picture -- the coupler is suppose to be just that - a coupler - not an adjustment device - with the coupler straight and aprox 1/8" gap - my stock coupler is still running
I have seen some setups with a 1/2" gap and the coupler used to make a turn --that will not work with silicone tube
get Teflon for that application and still avoid the gaps ! The Teflon will flow to a new angle -within reason and work -but it does not absorb vibes very well.

jamiem75

My Feedback: (2)

I only had about a 1/4 inch gap but i can't be sure if there was any bending in the coupler. It looked like it just got too hot. I'll get a new stock coupler and make sure it's set up properly.
Was the link for the teflon coupler "justengines.com"? I think it was something to that effect.
Anyway, thanks for the help.

Dirtnapper

Dick,
Why did you go back to the MVVS tuned pipe on the Showtime? You had a Skorepa carbon fiber pipe on your Funtana. I've noticed you really open the cowls on your planes for cooling. I think that was my probem on my Goldberg Sukoi, I was trying to keep as much of the motor as I could hidden ( which was easy in that big radial cowl ). I tried to make a fiberglass baffle for it but with the carb in front and all the throttle linkages and fuel lines, I could not do it.

Walt

pe reivers

Here is the [link=http://www.prme.nl/forum/viewtopic.php?t=55]very neat solution for fitting a teflon coupler [/link] of one of my customers.

devcon9

Thanks for the info, it is very neat.
Good flying
Tony

rmh

Thatr picture was handy - I am presently using the Skorepa - it is more silent /much lighter -- power is for all intents -the same mybe a bit more -depends on time of day ------