Project magnum
 

That poor GRRT........

Aren't you curious to see how that thing would run on right pipe? Any urge to get maximum power out of it?

Thats kind of of like driving a Corvette @ WOT with one tail pipe that is 1'' round. Then wondering why it is weak and don't run like other Corvettes.

Reward your engine and get the pipe. Your quest for power and speed will be over then. And you will never have to wonder how the other guys did it again. :D

Project magnum
 

Corvette, yuck :D
Give me a car that can handle our Cornish back lanes, or any corner for that matter lol

This pipe WILL fly on this setting just to see what happens, last time i was about on par with the Wests and now i have an extra 2K, tho i've lost an inch in pitch. Currently the weather isnt helping, and neither is being unemployed, can't go and throw 37 quid on a pipe when i have one here that "could maybe" work.
Having said that, the pipe Just Engines show on their site for the GRRT dosn't even look like a propper GRRT pipe, its missing the bit at the front which slips over the engines exhaust stub. The real GRRT pipe looks like a fit and forget item

Project magnum
 

I'd make sure you have it set at the correct length first... or else you might be shopping for a new liner and piston...:p And I bet they will cost more than 37£

Well maybe if your pipe is set 4" too short it won't do as much damage, but still.....

Find yourself a piece of alu pipe of the correct size, and some silicon tubing.... it can't be that hard to scrape sometthing together...
Even if you have to modify the plane to fit the longer pipe, it will be worth the time and efford...

An FAI pylon engine howling at the rpm it was intended for will make a nice addition to your website...:D

Project magnum
 

Well, the plane was designed to accept the pipe and even a bit longer, shorter is the problem as you can no longer point it out the top, hence the $h*t deflector in recent pics.
Would have been much better if i'd found out all this before i built, but its not really a problem, longer pipes are no trouble. Truth is the ability to run a prop on the engine was the last peice of the puzzle before it could be tested, untill then it had been a fan which at high pitch and 5" i would have thought comapirable to the props i would use, this was turning stupid fast so i didnt see a problem comming.
I'm already on the hunt for tubing ;)
Damn weather, I WANNA FLY!!!!! it's so crap i can't even take my boat out.
Big system sitting just out on the coast, so we get a hour of hard rain, then a hour of drizzle looks better, then the rain comes round again

Project magnum
 

I know the feeling...

We have the exact same problem over here... wind is blowing like hell, one minute the sun is shining, the next it is raining cats and dogs...

And it is probably the same weather system that is bugging us both...lol :p:p:p

Project magnum
 

well....
took it out, sounded better, lened it out, threw it, went rich, would lean out in the dives and came on the pipe for a few seconds, then went past like a wet fart, leaned out to ok fast by end of the flight, next flight the same thing :( next flight leaned it out a whole turn! reving good, not 25K tho, you boys and your 25k promises are getting a few undoubting blue comments from the guys on the field.
waywayyyyy, threw it went really good, then as it dived it went lean, on the flat it picked up and died, picked up and dided, tried to climb, but it died enough that i couldnt, but if i dive it picked up a little bit, after a few mins of this pissing around i counlt get it to cut at all, so i decided a low pass would cut the engine before i got to a point where either the engine cooked its self and died, or i stalled too low and died, the pass started well but the engine picked up and when i touched it was a little fast, the prop struck first, great, but it dug in, the rest of the plane didnt want to stop and this is the result. this GRRT is annoying me now. i cant even make it in flight mix adjust, not enough room and the needle setting isn't precditable enough

Project magnum
 

well ya know, I would mention using the matched GRRT pipe like everyone been trying to tell you.

But I can recall a very stubborn guy saying "I can make it work" :D

That butchered pipe is killing the performance that engine can produce. As for the 25,000 rpm's I haven't hit that but can get a good 24,500 or so. Next Time I have it out with tac I'll have to take a picture of it with tac to help make you a believer on the GRRT pipe.

:D

Project magnum
 

So your GRRT is annoying you now...?

Well, send it to me if you have no further use for it...:p:p

I'll let you now then if it really is a POS engine... or if it can really scream...hehehe

By the way, the damage doesn't look to be very extensive...
I can even see some oil soaked wood there that needed replacement anyway, so....
Sell you digital camera...then you can spend what you get for it on a MVVS pipe... and still have something left... maybe even enough for a new Magnum...:p:p

PS: Mine should have arrived yesterday or the day before... I'm starting to be afraid now it won't be ready for the weekend... damn...
And the guy who sold the kit to me is going on vacation this weekend... he will be gone for 4 weeks... damn even more...:(

Project magnum
 

no, the damage isnt bad, snapped the lip off the rear of the wing, took out the tank bottom, and wing plate, long crack all the way down the fuz and the top deck needs regluing. couple of days work.
im wondering if the strange behaviour is to do with a full tank, once its 3/4 empty you get a bit of air pressure and it changes the mixture from what it was at brimmy full. the fact my pressure nipple is pretty loose in the pipe cant help either.
I've got a 5" ali pipe extender, tho theres a guy somewhere with a 3 legged zimmer frame now :D wanted to try it like this first, it definatly picked up, but with the mixture being a pain in the ass i couldn't get any good result. I'd be tempted to buy the Just engines pipe if it looked more like the GRRT pipe and less like mine!

Project magnum
 

A short pipe will cause all of the setting problems you are having. Order the GRRT pipe, if it isn't the right pipe return it and order from another shop. If you still want to play with the pipe you have, set the pipe by using the measurement from the flange to the apex of the pipe, not the length of the pipe.

Unless you like experimenting and possibly wasting money, my motto is, always by the proper equipment the first time around. If you need to save a dime, buy it used.

Mark M

Project magnum
 

Some where in one of these threads on the Magnum someone mentioned an article on a dolly set up for the magnum. can anyone refer me to that article.

Or suggestions on a dolly system or landing gear of some sort.

I just hate to land a beautiful plane like this on its belly!
Just bought the package last weekend (too cool)

Project magnum
 

I'd be tempted to buy the Just engines pipe if it looked more like the GRRT pipe and less like mine!

Man you still not wanting to use the proper GRRT pipe. You already have a high revving and an expensive engine yet refuse to buy the proper pipe. Why even bother with the other ones out there when there is one designed for the engine you have?

Man don't be so cheap!.... :rolleyes:

You might as well just stick an OS 46 FX in the nose and not have to tinker with it anymore. IMHO i think you are wasting your time and violating your engines feelings! :confused:

Just make this one purchase and get the dang thing. Everyone been saying it from beginning so why not enjoy your engine instead of trying to rig it.

here is the link to the cheap and proper pipe. You pay that much with other pipes and headers together.

http://morrishobbies.com/product_inf...1ecc1ae428efa6

.40 GRRT Pipe FAI Pylon $55.95
3247

come on you can do it! :D

Project magnum
 

by the time it gets to the uk its 60 quid, thats a damn expensive pipe :p
i have to fix the thing before i worry about pipes again.
i wouldnt abuse it with a OS 46, a West 36 maybe...

Project magnum
 

Do you have one of those little baby birds in your pocket?

For some reason I hear something saying "I'm cheap, cheap, cheap"

:confused:

Project magnum
 

we dont all have the disposiable income of the average American flyer :(, in fact, im in negiative disposable.... :(:(
one question tho... it dosnt look like the propper GRRT pipe can be installed at much off the exhaust angle.. this might be a problem., it may not....

Project magnum
 

got the Magnum back together, the top deck is a bit stronger now, and the fit for the canopy better, i've also got a little hook that the fuel tubing passes through and if i wanna cut i can throttle back, the hook pulls the fuel line against the firewall and cuts the engine, unfortunally i cant make the servos movement presise enough to gently squeeze the tube to restrict fuel flow if it takes off and starts going rich.
Anyways, i fitted the 4" bit of tube i had and fired up, i instantly got 19-19.3 K so i had always been too short. without some friends to play with mixture, and someone else hold the taco while i play with pipe lenght ect i didnt bother making any changes. but with the pipe this long the canopy dosnt fit. might try at the weekend without the lid just to see what it does.
who was it that said "in a months time...." shut up and stop grinning you :p:D
my reason is, i might as well get the right length pipe just so i dont have to keep changing the canopy.

PS thanks to Helgefor his help, and my timing is exactly 180 degrees

Project magnum
 

Do you know what your straight line speed is? I'm curious to know just how fast these Magnums go (but *not* after a terminal speed dive).

Project magnum
 

we've had 165-185 range, this is using doppler shift, yes after a dive, but flying flat for a while after it, i've yet to see proof they do 200 on the flat.
i'm close in speed on a good run, but i'm very much down on RPM, sooooooooo you could say when i get the right RPM i will be faster.... maybe

theres a lot of drag in a open engine bay and pipe.

what the Magnum does have going for it is great flying qualites and "jet" looks over "yet another delta"

Project magnum
 

You can get a servo controlled onboard mixture control unit. The local pylon guys use them in their F3D models for in-flight mixture trim. Basically, they're just a 1/4 turn tap with a servo horn on them. It's the only way they can get the things to run on the ground *and* perform well enough in the air. Take off, climb out, go full lean and start shaking as you do 10 laps at 350kph :D

Project magnum
 

it would have to be pretty small, im lacking room in here, the GRRT's pick up actually faces the tank, but i've had to loop it a bit just to reach my hook, i suddenly thought the other night i could have made it precise if i had made it a ball link and its pulling when the servo horn is at the back of it travel, but its too late now coz the servo is glued in :D
Having the carb on the back of the GRRT has given me some headaches all the way

Project magnum
 

Mate, have you ever seen the inside of an F3D pylon racer? Space is most definitely at a premium! They use mini servos and yes, the mixture unit is tiny. It's just a tiny tap with a servo arm mounted on top. It makes things much easier, compared to arsing about with mixture on the ground and then crossing your fingers that it will be ok for the flight. I'm going to use one in my Murphy Mustang racer (if I ever get it going....pix of it on my site), 'cause I'll be in the same situation as you......my Nelson QM.40 has no carb either.

Project magnum
 

Project magnum got it's first run with the GRRT pipe yesterday, it went great, best yet on the 8x7, probably still too much prop for it tho. it would come off the pipe in climbs.
went fast enough to take the covering off the aileron which gave weird handling for the rest of the flight :D

Project magnum
 

Glad to hear that,

Because I can't wait to get my GRRT with pipe in the air......
The way it looks now I'll have to wait untill this winter until I've got my Vmax ready.

By the way, what's the weight and the wingspan / wingload of your magnum?
Cause I've still not decided wheter I'll increase the Vmax 110% or 120% to fit the GRRT. (Orgiginal it's 100cm wingspan for 3.5cc)

Project magnum
 

Hmmm... makes you wonder what they use to cover these things...

Are you using the correct pipe now?

Project magnum
 

the wingspan is as standard, what ever that is lol
all i did was hide the engine and pipe in the unused canopy. i think i'm about the same weight as the Wests without the drag. havent checked for sure.
its a propper pipe now yes.