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-   -   Magnum 80 (http://www.rcuniverse.com/forum/twin-multi-engine-rc-aircraft-192/10057130-magnum-80-a.html)

NoOneFlysAtMyClub 10-08-2010 11:10 PM

Magnum 80
 
1 Attachment(s)
Thought I would share my latest project with twin fans the world over!!!

Magnum 80 built from a short kit by www.lasershortkits.com

Power is two Super Tigre S.45K ABC engines with Jett tuned mufflers.

Vess 10 X 6 props.

I should call mine a Magnum 90!!!

Tail dragger. Main gear and wheel pants are off a damaged Sea Bee.

Have not weighed it yet.

Here are some pics.

Tony


Carlos Murphy 10-08-2010 11:53 PM

RE: Magnum 80
 
Great looking plane.

91zulu 10-09-2010 12:22 AM

RE: Magnum 80
 
That look sick..super man SUPER..When you fly it can we get vids?

DelRay 10-09-2010 07:43 AM

RE: Magnum 80
 
Tony, very nice looking twin project, I love the trim scheme, and it looks super fast just sitting on the bench. Thanks for sharing the nice pics.[sm=thumbs_up.gif]

earlwb 10-09-2010 08:06 AM

RE: Magnum 80
 
Cool plane, can't wait to see your flight reports and maybe a video too.


Kmot 10-09-2010 10:20 AM

RE: Magnum 80
 

Quote:

ORIGINAL: 91zulu

That look sick..super man SUPER..When you fly it can we get vids?
+1 :D

xlr82v2 08-21-2012 04:26 PM

RE: Magnum 80
 
Anybody know where you can get plans for the Magnum 80? The link for lasershortkits.com is dead.

Ripon 08-24-2012 01:33 AM

RE: Magnum 80
 
I don't have the plans but I do have the original build article from September 1978 Flying Models which I could probably scan and put up as a pdf. Been wanting to build it for 34 years now, must get roun to it!
John

xlr82v2 08-31-2012 11:40 AM

RE: Magnum 80
 
Ripon,

Thanks! It would be good to see the construction article, could you scan it? Thanks!!!

Ripon 10-05-2012 06:57 AM

RE: Magnum 80
 
1 Attachment(s)
Construction article attached - been waiting to grt my scanner fixed!
John
Files are too large so I'll send in 2 posts.

Ripon 10-05-2012 06:58 AM

RE: Magnum 80
 
1 Attachment(s)
Next two.

xlr82v2 10-05-2012 11:52 AM

RE: Magnum 80
 
1 Attachment(s)
Awesome!!!!

Thank you very much!!!

:D:D:D

Hope you don't mind, I assembled the 4 pages into 1 .pdf file for easier viewing...[8D]

NoOneFlysAtMyClub 10-06-2012 07:35 PM

RE: Magnum 80
 
1 Attachment(s)
Hi all,

I still have not flown the Magnum yet, so no video.

Life got in the way.

I will rejoin AMA and a new club 1/1/13.

I have been busy building though.
This is a Big Apple turned into a six engine sorta bomber looking thing.
Another Dick Sarpolus design.
It is fairly similar in design; same wing, same fuse formers from the wing saddle back and same moments.
Different fin, stab and fuse, forward of the wing saddle.

I made a few changes to every part of the plane. Fully sheeted structure, film covering, fixed gear because there was not enough
thickness to the wing for my dual tire set up.

Power is six MDS .18's with 4oz tanks. One 9 gram servo for each engine.

Here are some pics.

Tony

xlr82v2 10-06-2012 09:26 PM

RE: Magnum 80
 
WOW!!!

Now that is COOL!!!

We will definitely require some video of that fine machine in flight!!!

NoOneFlysAtMyClub 10-06-2012 11:18 PM

RE: Magnum 80
 
Thanks!

If I can, I will find someone to shoot video of both planes.

Glad you like them.

Thanks

bentwings 10-19-2012 10:04 PM

RE: Magnum 80
 
I built 2 of the Magnum 80's back shortly after article came out. Then 2 more a few years later.
Originally I had 2x K&B 40's. At the time twins were not cool and not at all popular. Being deeply involved with drag racing at the time I flew these like I would run the Funnycars...flat out

It took a while and one plane to get comfortable with the twin as a daily flyer. We had a very short runway by todays standards so brakes were necessary. Not much was available so I made my own. Servos were expensive for the radio I had. There were Rohm retracts on both planes as well as the later ones. I used A/C freon to operate them. It was dirt cheap then. I made my own fuel as I had ready access to nitro,alcohol and Klotz oil. It was not uncommon to hit the field with 18 glow plugs, several gallons of fuel, dozen props and a flight box full or misc stuff. Sometimes I would leave the field owing props and glow plugs to everyone. I was an environmental disaster everyday. haha

I blew up the original motors pretty quickly as the planes were very fast and the motors unloaded a lot in the air. I had 2 speeds...full throttle and idle.....usually one motor out landing. the second generation motors were K&B 40 with fuel pumps. these ran terribly together. I occasionally used up a gallon or more fuel and never got in the air fooling with them. I made it even worse adding tuned pipes from my Dirty Birdy 40's.

The 3 gen motors were K&B 6.5 rear ex with tuned pipes and fuel pumps similar to the article. It took a while to get them running well but when they ran they were awsome. The cops recorded 125+ mph many times. Their radar seemed to miss after about 125 and would just not read. Eventually I added more nitro and the motors really got with the program. I finally blew a rod right out the side of one and the other had a cracked piston. I repaired them and ran them untill the head bolts stripped out.

Later I built another pair and flew them for a couple more years before one crashed in a cloud of pieces and I retired the last one.

There was a later version of this plane that I never built. Somewhere I still have plan for both. haven't seen them for years.

If I was to do it again I'd probably put some modern 60's on it and longer gear legs, brakes would be nice. A separate flap arrangement would slow tha landing down a bit. Todays radios are much lighter so you can cut the weight down some. I liked the fully sheeted versions much better. The vibrations quickly destroyed the first wing. I replaced both wings with foam core and fully sheeted. Much better. The last 2 were built up but fully sheeted. One layer of 3/4 oz cloth, one coat of thin primer, sand and one more coat of thin primer, one coat of thin paint. that was it.

I have ony one surviving picture somewhere. I'll try and dig it out.

Good luck on your build. These are great flying planes with reliable motors.

xlr82v2 10-20-2012 05:06 AM

RE: Magnum 80
 
Bentwings,

Thanks for that report!

I'm wanting to build one of these with 4 stroke power, thinking probably going with .70-.80 size engines, maybe .90's. High pitch props since the 4 strokers can't turn the RPMs that the 2 strokes can. What's your opinion on that? But, I love 2 strokes also, so they aren't out of the question either.

You said foam core is the way to go? Thanks for that advice! What kind of foam did you use? Would you recommend the blue or pink eps foam, or the white "beaded" foam? I've never built a foam wing before, but I built all the foam cutting stuff I need (nice power supply, automatic feathercut type machine, bows, etc) as some rainy day projects a few years back... so I'm set there... just never have used it!

Also, did you build the anhedral into the tail, or just leave it flat?

bentwings 10-20-2012 07:44 PM

RE: Magnum 80
 
I'm not a 4 stroke guy so I can't speak with knowledge of them. I do think you would have to make major modifications to the nacelles as they are not very wide or very deep. This plane had very good engine out characteristics ....at least mine did with the high speed 2 strokes and relatively small diameter high pitch props. I would think 4 strokes with large props may change this for the worse due to the low speed torque. The other thing is the weight. I don't remember having any lead in the planes. The long "stick out" of the motor may make it nose heavy. This plane is a pattern plane and as such is designed to be very fast and stable. I would not plan on "lumbering around the sky" with this plane.....it would be just wrong...haha

I think today ifs I were to do foam wings I'd use pink. It seems to be finer grain so it sands much easier. I surely would weigh samples of each. My original replacement wings were cheapo white bead foram. A mess no matter how it is done. But that is what was used back then. I made my own foam cutter back then too. I didn't really know how dangerous they could be....just lucky I guess. I installed a big variac in a home made lite ply box and made the bow from thin wall chrome moly tube. there were round ends that I made wood insulator bushings for the wire hooks. The wire was nychrome I got from somewhere. Thinking back I cut the cores on a big steel welding table at the shop I worked at. can't you just see the sparks fly. OMG was I lucky.!!!

Be sure you plan out the landing gear ahead of the build. It's pretty short so bigger props will take longer legs. the nose gear was the weak point and I often dinged props landing and braking.

I used the anhedral in all of them....I'm not an aircraft engineer so I saw no need to change it. Besides it looked cool and seemed to work great. The updated version uses a straigt stab. I think it is lower in the rear of the fuse too.

This is a very easy plane to build. I think I built 2 of them in a month or so. I was a hard living soul back then..there was never enough time in a day...sleep was a waste of time. haha

Goodluck. this was one of my all time favorite planes


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