Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

MagnumR dolly

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Old 07-09-2004, 09:44 AM
  #1  
KevinS
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Default MagnumR dolly

I am posting this because of the lack of information around on these dolly's. I dug around various peoples ideas, and came up with the following. I decided to build one because I use to have a diamond dust and knew from experience that these fast planes can be a handful to hand launch. I haven' t tried it yet, so I don't know if it works, but I don't see why it wouldn't. I will post on how it worked once I get a chance to fly this thing.

Of note, people are commenting about how the fuel tank on the magnum-R is pushing down on the wing, causing a gap between the fuse and wing. On my kit, there was a note stapled to the front of the manual that stated that they had found a problem, and instructed me to dremel out the former to allow the tank to sit 3mm further into the fuse. I did this, and then had no problem with the tank pushing the wing out. Overall I am happy with the kit, the clevis's are too large for the elevator bolts, you have to replace them. But everything else fit together well. Engine mount was even already bolted to the fuse, impressive. But there isn't much room to get the fuel lines from the tank out from behind the engine...tight tight tight. I am hoping the fuel lines don't kink in there.

Basically the dolly is just a hunk of plywood, 4 inches across. I have a landing gear w/wheels screwed to the wood at the front of the dolly. I put a tail wheel I had laying around at the rear. To allow me to tweak the tail wheel direction to get the dolly going straight, I attached a ball-link to the bottom of the dolly, and ran a rod with a z-bend to the steering mechanism on the tail wheel. If it doesn' track straight, I can pop off the ball link, and adjust the length of the linkage, and counter the turn. I used a nail just behind the landing gear, and cut it off so that it sticks up about 1/2" to act as a pin to drag the plane along (this didn't show up in the picture, but I circled where it is). There are two vertical sides at the rear of the dolly just to keep the plane on, and not swing off, they don't actually hold the plane down. I put a 'T' nut in front of the wing, on the bottom of the fuse (see pics) for a place for the pin to go in. The plane just sits on top of the dolly, and lifts off very easily. I think this should work well (In theory, I will find out real quick at the field
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Old 07-09-2004, 11:58 AM
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Default RE: MagnumR dolly

I made one for my GP Patriot. I am just about to buy the new tigershark, but if yours works well for the R, I might go for one of those!!
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Old 07-10-2004, 05:53 AM
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Default RE: MagnumR dolly

Hi Kevin,
I'm not a fan of hand launching either, so I made a dolly for my Magnum around a year ago.
Initially I had a fixed tailwheel similar to yours but found that it wouldn't track straight down the rwy. So I ended up making the tailwheel steerable by installing a flight pack to the dolly (Rx, Battery and servo). It works perfectly........[8D]...........All I need to do now is learn how to land on it...........
Good luck with your dolly, one thing I do know is you'll never go back to hand launching once is sorted.
Cheers
Ken
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Old 07-10-2004, 05:28 PM
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Default RE: MagnumR dolly

Well, the dolly works, but barely. Its barely getting off, once it didn't, and the pin is scraping along the bottom of the fuse. I think I will try putting dowels in front of the wing, an cut out the pin. But since it did take off, I was able to get it trimmed and we tried hand launching it. hand launching worked fine, it pulls out nice, with no bad tendicies. flies like its on rails like everyone says, nothing difficult about it, except for staying with it, if you lose your orientation your toast. Still running the 9x7 prop, and the engine is still breaking-in, but it moves along. I would say about as fast as my old diamond dust did with a rossi 45. I will have to order the 8x8 props so we can take it to the next level.

One thing that confused me was many on here say how much of a brick it is, but I put my cg at 140mm back, and this thing glides in real nice. I don't have any problem controlling it at low speed, and can glide it from very far out. It glides decently....now my pizza box...that something that doesn't glide!
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Old 07-11-2004, 02:40 AM
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Default RE: MagnumR dolly

So how fast do you reckon its going with your current setup?
Encouraging to hear that your low speed is good. How slow will it slow down, and still be flyable?


Cheers,

btw..on my GP patriot dolly, i used dowls just infront of the wings. Make sure that they are high enough not to allow premature lift off, so if possible, make some adjustable height ones.
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Old 07-11-2004, 07:43 PM
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Default RE: MagnumR dolly

The dowels work much better. The problem with the pin is that it was too short, the tail of the plane would come up, and the plane would come off the pin before it was ready to fly. The pin was also scratching up the bottom of the plane bad. So with the longer dowels, the plane sits on the dolly longer, and gets away very clean. Plus the dowels won't scratch the bottom of the plane up.

I don't know exact speeds for how much its slowing down, but it slows down good enough for me. My biggest problem is getting the engine to quit when I want, it takes it a while to finally shutoff and then I am coming in too hot. I am learning to let it die further out, and depend on the glide.

The guys at the field today thought it was doing about 120mph. I will be ordering the 8x8 props tonight, but I probably want use them until I get a few more flights under my belt.
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Old 07-12-2004, 12:36 PM
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Default RE: MagnumR dolly

Sounds like your magnum set up is what i want. Top speed of over 100mph, and a low speed thats "good enough" for someone!

other question. Did you enjoy flying it?

Cheers
"nervous" Dave
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Old 07-16-2004, 12:31 PM
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Default RE: MagnumR dolly

I put the APC 8x8 prop on and shortened the header by 1 inch per directions. I leaned the engine out as much as I could on the ground, but upon launching it barley got off the dolly, not near as much pull, and in the air it was way slower then the 9x7 prop, probably only around 100mph. Any ideas? I can't lean it out any more it will shutoff on the ground before I even get it in the air. Richening it of course, just lowers the RPM. I am getting some smoke in the air, so its not too lean. It doesn't even sound like its getting as high of a RPM with the 8x8 as I am on the 9x7.
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Old 07-16-2004, 02:36 PM
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Default RE: MagnumR dolly

could you post a picture of the magnum on the *updated* version of the dolly

Cheers
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Old 07-17-2004, 11:21 PM
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Default RE: MagnumR dolly

ORIGINAL: KevinS

I put the APC 8x8 prop on and shortened the header by 1 inch per directions. I leaned the engine out as much as I could on the ground, but upon launching it barley got off the dolly, not near as much pull, and in the air it was way slower then the 9x7 prop, probably only around 100mph. Any ideas? I can't lean it out any more it will shutoff on the ground before I even get it in the air. Richening it of course, just lowers the RPM. I am getting some smoke in the air, so its not too lean. It doesn't even sound like its getting as high of a RPM with the 8x8 as I am on the 9x7.
What RPM are you getting on the 8x8? You have the west 50 VI correct? My engine with the 8x8 didn't like it when I cut the header shorter, with the header stock length, (assuming mine was the same as everyone else's) on 15% nitro with an APC 8x8 I get 21,500 on the ground. That combo give me about 190mph in a slight dive, about 170 in level flight. Make sure you're running a nice cold plug, I use the OS R5's I believe they are, they are an RC car plug. Also, I put the large diameter fuel tubing on it, the medium just didn't seem to let the fuel flow as well. Also, make sure your header and pipe are close together but not touching, you don't want much more than a 1/16" gap between the 2. Make sure the prop is balanced as well or you'll lose a lot of RPM's.

On my West 50VI in my Whiplash with the custom header that weston made for me I somehow manage a wicked 24,000RPM off that engine. Philly baby and I have discussed it and cannot figure HOW that engine is doing that much RPM but it's awesome. It just screams, makes the one on my magnum sound quiet LOL
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Old 07-21-2004, 03:51 PM
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Default RE: MagnumR dolly

Who needs a dolly

http://bornholm.adsl.dk/modelfly/fil...gnumLaunch.wmv
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Old 07-22-2004, 04:03 AM
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Default RE: MagnumR dolly

MY west 50V1 is eating plugs. anyone know why? After i stop the engine i let it cool down and when i try to start it up, the plug is dead. I use OS NO8.
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Old 07-22-2004, 04:14 AM
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Default RE: MagnumR dolly

Mine does that too if I runt it too lean.

I have tried to run fuel without nitro, and it seems the plug also lasts longer
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Old 07-22-2004, 05:10 AM
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Default RE: MagnumR dolly

Add a head shim or two. Is it a new engine, and has it been eating plugs since you got it, or is this a recent development? A new, tight engine will often eat plugs. Not so common these days with ABC/AAC engines, but in the old iron piston days the engine would eat plugs until it broke in, so you'd add a couple shims during that period.
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Old 07-22-2004, 10:29 AM
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Default RE: MagnumR dolly

On a modern model engine, with very few exceptions, the only thing that causes a plug to blow is a lean run. This can be either from setting the engine too lean for launch, or can be caused by an air leak somewhere causing air bubbles in the fuel, or foam in the fuel caused by airframe vibration.

Remember, a piped engine will require more fuel when it unloads in the air, and should always be launched slightly rich to accomdate this.

If you are getting a good needle on the ground, are certain you have no fuel system leaks, and are launching rich........ and the engine still goes lean and blows plugs in the air...... the culpret is fuel foam. I would first make sure the fuel tank is properly padded and not touching any airframe structure.

What aircraft is it installed in ??
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Old 07-23-2004, 05:13 AM
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Default RE: MagnumR dolly

Thank you all!! My engine is spanking new only used 4 times in my MagnumR. I will try to run it richer next time! what OS plug do you recommend for my west? How much RPM should i get on a 9x7 on my West 50 V1
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Old 07-29-2004, 05:47 AM
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Default RE: MagnumR dolly

you must have got your dolly to track nicely by now. please can you tell/show me the current orientation of your tailwheel.

(it'll give me somewhere to start, and wont track as badly as a first trial)

your set up is, v1 piped, apc 9x7, 10% fuel??

(mine aint an "R") shouldn't matter


Cheers
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Old 07-29-2004, 07:24 AM
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Default RE: MagnumR dolly

G'day Dave03B,
Might be worth your while making your dolly steerable, here's a couple of pics of mine.
Making it steerable solved my tracking problems due to bumpy runways. The Magnum looks awesome screaming down the strip...........[8D]
Spent the last year now trying to land on it.................
Cheers
Ken
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Old 07-29-2004, 07:53 AM
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Default RE: MagnumR dolly

could i use an old tempremental rx that's been in a crash, to steer a tail wheel?
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Old 07-29-2004, 10:52 AM
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Default RE: MagnumR dolly

Kevin, how high are your dowels?
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