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-   -   Project magnum (https://www.rcuniverse.com/forum/extreme-speed-prop-planes-104/574437-project-magnum.html)

Cactus. 02-21-2003 04:22 PM

Project magnum
 
Project Magnum has begun.
MVVS GRRT in a Weston UK Magnum
www.philsrcworld.fsnet.co.uk
lets see if this pic link thing works
http://www.philsrcworld.fsnet.co.uk/...ghwithcowl.jpg

Razor-RCU 02-21-2003 05:25 PM

Cool!
 
Please keep me posted as I have a GRRT that needs a home-

Got pics?

james

Cactus. 02-21-2003 08:18 PM

Project magnum
 
1 Attachment(s)
pics and a full building review all on my site.
for tonight the canopy now fits with the engine and pipe in place, the nose needs engine bearers fitted ( damn needles being right on the same line as the lugs, anyone know of an engine mount that will will work or wont mind being hacked up a little? ) and the floor put in above the tank ( still enough room in there for a SLEC 6oz! )
The whole transformation has been quite easy really, and depending on results is definitely worth it if you have a West 50 and don't mind cranking the engine over and loosing a big lump of drag in the canopy.

lets have a poll IF i can work out how..... the fuz is loosing quite a bit of film and will need recovering.. i did think about redoing the whole plane a different colour and sticking back on the CF stickers.
can i only start a poll on the main thread? damn...
ok..

LEAVE YELLOW WITH STICKERS
RECOVER WHITE WITH STICKERS
RECOVER ( SUBMIT COLOUR ) WITH STICKERS

very bad quick photoshop of a white magnum.
Quite how you replace differnt shades of yellow with the same differance in white is way beyond me

Cactus. 02-21-2003 08:58 PM

Project magnum
 
1 Attachment(s)
just for fun heres a few colours in a Andy Warhole (?) style against a untypical Cornish blue sky.
leave the pic do its thing

Rudeboy 02-22-2003 02:07 AM

Project magnum
 
I'd say if you plan on redoing the whole plane, take a real visible colour and leave those big stickers off... saves you some weight...

Can't you take a standard engine mount and put a couple of strips of alu under the engine mounting lugs to raise the needles above the bearers?

Cactus. 02-22-2003 10:19 AM

Project magnum
 
The engine is aready sitting very low to hide as much of it as possible, it means i cant lower the mount any. Im hoping to find a mount that is solid enough to cut a little away, most now have the two arms and just webs below.
I really think it needs the stickers.. tho i was going to put neon orange wingtips on the bottom or some more of the CF film for wingtips if i went white beause i have two sets of stickers. This would make it stand out better on our normally grey skys. The yellow Magnums do really stand out, im kinda torn between that, and having a white one.

Cactus. 02-22-2003 09:04 PM

Project magnum
 
i had some help today
http://www.philsrcworld.fsnet.co.uk/...es/helper2.jpg

Nose is shaped, more to come. keep checking the site for updates

Cactus. 03-04-2003 05:17 PM

Project magnum
 
page updated again and a little movie of a engine test added
http://www.philsrcworld.fsnet.co.uk/...RRTrunning.jpg

i also have a page with a Doppler shift speed measurer program to download

FlooredCOBRA 03-04-2003 06:35 PM

Project magnum
 
phillybaby

what prop are you running on your GRRT?

Cactus. 03-04-2003 10:19 PM

Project magnum
 
That was a APC 8x8, the GRRT has flown on that before and i know its not the right size, its was just something to use untill i can find the size i want

FlooredCOBRA 03-04-2003 11:57 PM

Project magnum
 
Okay I was wondering because it did not sound like it ever got up on the pipe. I am sure it would work pretty good with a little shaved off some.

Cactus. 03-05-2003 06:16 PM

Project magnum
 
it wasn't leaned out, tho it dosnt pick up much when i do. heres a list of props i can get hold of
http://www.alshobbiesstore.com/acata...ellers_67.html

FlooredCOBRA 03-06-2003 12:41 AM

Project magnum
 
maybe you are over propped. When you get up on pipe you should able able to tell a huge difference and a 7000 to 8000 jump in RPM's.

Thats the way mine does and its a GRRT. they should run the same. If it does not kick up on pipe it just sounds like a regular engine with a pipe hooked up to it. and no advantage from any other engine.

Maybe try shaving your prop some and see what kind of numbers you can get on the ground.

Cactus. 03-06-2003 10:40 AM

Project magnum
 
i don't think its the pipe that comes with the engine. whether this will make a difference i don't know. 7k jump is HUGE!!!!! like when it was running on the 5" fan :D
what should i shave it down to and how? i've never done that. i still have to get a balancer and taco. would the 7x8 be a better choice? 7x9?
i also currently have the 9mm carb on and i have to give it some more breathing room. i know this engine ran in this plane http://www.philsrcworld.fsnet.co.uk/...s_files/dd.JPG
on a 8x8 it was doing about 150 and with a 8x10 160-165 the figures may be wrong because i was standing in one point and timing a run between cones from a distance. however the difference in speed is accurate.

FlooredCOBRA 03-06-2003 11:40 PM

Project magnum
 
MVVS makes a pipe that is made for the GRRT. I would try that pipe out and see if you get different numbers.

If not shave of just the tips of the props like a 1/4" maybe a little more.. I did this with a 7.4 X 8 and finally got it up on the pipe. You will know when you have shaved enough because it will run WOT and have like a 2 second delay then get up on pipe. Well at least thats how it does on mine. It wont directly go up on pipe, it has a short delay. But you will know when your on it or not. It sounds pretty loud.

Cactus. 03-07-2003 12:01 AM

Project magnum
 
why don't i just buy a 7x8 then :confused: :confused:
how do you shave your props? chop off the ends and rebalanced or shave it back to the rough tip shape??
I'm a cheap skate ( loosing job dun help matters )... the Magnum was £30, the engine and pipe £15.. i have a pipe, i'll use it unless it explodes :p buying a new pipe isn't on the cards. its a hell of a pipe tho. my ears where ringing after that test run for at least 15 mins afterwards.
I have to order the servos so i'll get a couple of 7x8's at the same time. wonder if the APC will stand the RPM.. is there a thick hub option at that size? i gotta take it out to 7mm after all. if they cant take it i guess i'll have to go wood

FlooredCOBRA 03-07-2003 03:34 AM

Project magnum
 
well the reason I said to use 7.4 X 8 is because it is a Racing Carbon fiber prop. It has kind of a funny shape to it also.

The hub on it is a D1 instead of the standard C2. The D1 one hubs are much thicker and can take the abuse of a high revving engine better than a C2 hub.

I am sure you could just use a 7 X 8 prop from start. It would probably work too. But it is not designed for higher powered engines as the Carbon fibered prop is.

Shaving a prop probably is done different by each person that does it. What I do first is cut off the tips to a length I want. I am guessing what may work from start. You wont know until it is on engine. From there sand it to the shape of the prop as it would normally be at the tip. Then just balance it out and see how it works.

I am sure there are probably easier ways but this way seems to work with me. Sometimes it does not work and I have to take back off and shave off some more to get it right. But you will know when you have it by the increase in rpm's.

What RPM's are you getting right now by the way?

Cactus. 03-07-2003 11:04 AM

Project magnum
 
no idea what RPM's, i have no taco.. when i find where those nice and cheep pocket ones are i'll get one.. reminds me, i have to buy those servos and props today... i really didnt want to go carbon if i didnt have to, i saw one last one flight a while ago, a normal APC would have survived the slight ground touch it got on landing. too expensive to fragile

FlooredCOBRA 03-07-2003 10:09 PM

Project magnum
 
they have other ones that are D1 hub size but the sizes vary. to get a certain size it may be carbon or not carbon just to use that size prop. that is the only reason i ended up with the carbon prop. Was only because the size i wanted was only in carbon.

check out www.apcprop.com

Cactus. 04-18-2003 07:50 PM

Project magnum
 
shes done, shes almost a match for the West's and theres still more in that engine i know it
www.philsrcworld.fsnet.co.uk

SSAN 04-19-2003 02:52 AM

Project magnum
 
Phillybaby,

According to your pic on post #14, I know that engine is NOT a GRRT Pylon 40. I have two of them, and the MVVS GRRT Pylon 40 is a Rear Induction and Rear Exhaust with open Venturi and a full wave tuned pipe. The engine should turn in excess of 21,000 rpm with 8x7 prop if it's a GRRT while running on the ground.

The engine you have look like a Sport motor with the exhaust turned backward. Also, MVVS don't make FAI Pylon Racing engine in Front Intake Rear Exhaust that I know of, at least for now. Hope this clarify it...

Cactus. 04-19-2003 07:13 AM

Project magnum
 
That pic is of the plane, not the engine, that plane did have the GRRT in it after this pic was taken with the tuned MVVS 40 and black mini pipe, this pipe was also used on the GRRT. if you look at the very first pic you can see it is indeed a GRRT, tho the pipe isnt a MVVS item which at the moment i think is robbing my speed, i've taken about an inch off it and its still not screaming like i've been told it should. can anyone tell me what the pipe length should be and where the reflect point is on the pipe as in pic one. it might be too long still, but without changing the plane i cant make it any shorter

jetsett 04-22-2003 04:12 PM

Project magnum
 
Maybe you should learn how to tune a pipe, rather than asking, " can anyone tell me what the pipe length should be and where the reflect point is on the pipe as in pic one. it might be too long still, but without changing the plane i cant make it any shorter"

When you do know how to tune a pipe, Make sure you tune it BEFORE you install it. Just trying to lend a helping hand.

Don

Cactus. 04-22-2003 07:53 PM

Project magnum
 
I can tune a pipe, but with no throttle theres no jump to pick up on, its picked up from 14.8k to about 18-20k now with no real "on the pipe" jump in rpm i'd expect once i got it right, each 1/4 inch off has improved it, but having been told the GRRT can do 21k AND 30K with a 4K jump when you hit the pipe i have no idea what to believe. All i can do is keep chopping up the pipe ( have to get myself a taco to help with this bit ) and keep trying it, but with out knowing more i could make it too short, then have problems with over long silicon and a spacer ring which i don't have room for in the canopy, silicon entering the canopy i can manage ( as it is now ), further than this I'm screwed on space, making the pipe any shorted is also a problem. This is why asking people that know already is the best option.
This pipe isn't for this engine, so is probably the wrong length, and I'm not sure where the reflect point is for a full wave pipe as i've only ever had baffled pipes, I'm guessing at the stinger, but i could be wrong, i also don't know the piston to reflect point length for a GRRT, knowing this would help a lot and let me know if i've gone too far, or have to come shorter.
As you like to point out to me time and time again Don if you don't know the answer shut up.

deckerv 04-23-2003 05:33 PM

Project magnum
 
Phillybaby.... nice homesite by the way!!! Very cool vids!!!


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