maverick

My Feedback: (12)

Well I took my Weston Magnum out for the first time yesterday and it turned out to be a total disaster!

With the help of a friend, I spent a while breaking in the engine and getting it all dialed in right and then one of the senior instructors at my club who has flown racing planes previously offered to do the first flight. I had made a vow to myself to do all of my first flights, but seeing as this thing was a whole lot faster and the instructor had the experience I thought I would let him do it.

Well we got it into the air from a hand launch and the thing rocketed away, but it was extremely uncontrollable. After only a few seconds the thing just flew straight into the ground in a seemingly uncontrollable dive. There was apparently no control at this time.

Well we walked out to it and the plane was smashed into many pieces. The header was broken off the engine and there were pieces spread around everywhere. The whole front of the fuselage still with the engine firmly on the mounts was separated from the tail end of the fuse.

Now at first thought it seemed to be way over controlled. But the throws were set exactly as per the manual and there was -50% (Futaba) expo on elevator and -25% expo on aileron. The balance point was right on the forward mark too.

We had done a range check and the whole time we were breaking in the engine we never had any radio glitch or interference.

When I got home I re-read the instruction manual and noticed it says that this plane is very stable and loves fast sweeping turns. Well this was way different to our experience.

Has anybody else had problems with flying their Magnum?

Any suggestions as to what might have happened?

Does anybody know if Weston UK have any sort of warranty on this type of thing?

I am now a little turned off this plane and have started researching an alternative airframe to get the necessary speed experience for jets.

Any suggestions?

flybike

Sorry to hear about the crash. I will be watching this thread: I just ordered a Magnum a couple of days ago. Any thoughts of anything you would do differently? I have a new Hitec Eclipse, but have never used expo before on any of my sport planes. Do you reccommend negative exponential on the Magnum? Thanks, Hans

Cactus.

My Feedback: (1)

i've only seen this on a Magnum copy, but that was just too much rate, a nervous first flight, ok after that. it takes a couple of seconds to get control after launch while it gains speed, i suppose if its over controlled during this period it might snap when it's up to speed. i'll find out about the movements and rates used on all Magnums here.
There isn't a warranty for this, might blag a few $ off a new one tho if your lucky.

maverick

My Feedback: (12)

After reading back through what I just wrote it sounds like it crashed on launch. Well it definitely wasn't a launch issue. After launch it did sag down quite low to the ground but was up and flying well after this. When I said a few seconds after launch it was probably more like 10-15 secs. The plane was definitely flying and was reasonably high when control was lost. Then it just went in.

I have all of the pieces in a bag in my workshop and I am about to go out there and sift through it for any clues.

maverick

My Feedback: (12)

Actually after this experience I don't know whether I would get another one! Assuming the engine and pipe are OK, can I just get the airframe and header? Any idea on how much in US$ it is?

Traxxas_Tech

My Feedback: (22)

Whiplash - Whiplash - Whiplash!!!

I thought about the Magnum, but heard too many good stories about the Whiplash. Its lighter too!

Rather than another Magnum, I'd maybe go with the Wiplash if you decide on another "fast" plane.

Sorry to hear about your loss

Cactus.

My Feedback: (1)

whiplash still dosnt look like a jet even if it goes like one.
yes, plane is avaiable seperate. how is your RX installed? i read a new artical about one just banded and the crystal came loose.
how did you do the wing bolts? i hte the kit standard, did they shake loose? did you loose one control and not the other? clues clues clues. Magnums don't just fall apart on you

maverick

My Feedback: (12)

That is what first interested me in the Magnum. It sure does look like a plane, whereas the flying wing types don't really interest me. Although now I am going to look closely at a Whiplash.


The receiver was wrapped in foam and then a wire tire was put around the outside of the foam. It was then placed inside the plane exactly where the instructions said. When I did the post-mortem today all of the radio gear was still connected and functioning properly. So no clues there.


The stock wing bolts were replaced with nylong bolts into blind nuts. These definitely didn't come loose as the mounting plate from the fuse is still attached to the wing. On impact the wing bolts held and pulled out the mounting plate from the fuse.


Not that I can tell. Both elevators are still connected to the servo. The servo was still connected to the mounting plate, but the plate had come loose from the rails in the fuse. Now I don't know whether this happened before or after impact. The elevator servo mount was secured to the fuse exactly as per the instructions. The ailerons were still both connected to the servo too.


Yes, I know clues are the key to figuring out what happened. That is why I brought home all of the parts in a bag and did a post-mortem today.

I haven't found anything suspicious looking that could have caused it.

The radio is still working. The aileron servo and connectors are still all intact. The throttle servo arm was broken off, obviously on impact when the whole plane from the firewall forward separated, but the connector on the throttle pushrod is still secure so this wasn't the issue.

All of the tail feathers are still intact so there was no issue there.

The engine is still firmly mounted to the mount which is still firmly mounted to the firewall, so no issue there.

In my mind there are a few likely causes, but I cannot say for sure if or which one it is:

1. The elevator mounting plate broke loose whilst still in the air.

2. The pipe moved forward and was touching the header causing vibration that created radio interference and a loss of control.

3. There was just too much control throw and thus at high speed the plane was uncontrollable. (Although the throws were set as per the manual.)

4. The pilot made a control error. (Unlikely due to the person's experience, but I guess possible.)

It didn't fall apart in the air. It augered into the ground at high speed.

Cactus.

My Feedback: (1)

didn't think of the pipe thing, i normally keep at least 2-3mm between the bits, blowing the silicone isn't as expensive as blowing the plane. what was your starting gap?
i've had the radio tray come loose in my Cougar, gave me a funny elevator and it linked to throttle, made for interesting landing, pull up to slow, throttle up. I've had the same bad luck as you before. it's so tempting to give up on a plane you brought for a good reason in the first place.
Whats your wing like? a new fuz shouldn't be too hard to make. all bits are available separate, but a new kit would be cheaper than 50-60% new parts.
i've also had a test pilot kill a plane on a test flight, purely dumb thumbs. lucky i'm now far enough along i can test any new plane

maverick

My Feedback: (12)

The starting gap was at least 3mm. When I mounted it I pushed it hard against the header and then withdrew it some. The I tightened the straps.


Well this is my first total destruction of an RC plane. I have been flying for 2 years now and have only crashed 1 plane. It was a World Models P-51 and I stalled it trying to turn back to the runway after a deadstick. It was totally repairable and is still flying now. My son also crashed our LT-40 trainer when I had him on the buddy box. He was flying past us and did a turn towards us and over our head instead of away from us. By the time I let go of the trainer switch and took control it was too late. This was totally repairable too and is still flying.

I am real tempted to give up on the Magnum right now. Not just because of the crash but it was a bit of a pain to put together. Some mods had to be made and the mounting of the engine to the mount and the mount to the firewall wasn't possible the way the instructions said. Also the cowl cheek had to be modded to allow the header to fit properly without touching the cheek.

There were a few other things like the wing mounting bolts that needed mods and one of the blind nuts in the firewall being full of glue etc.


The wing was fine except for a broken aileron. But now it is in two pieces as during the post mortem I wanted to see what it was built of and broke it in half. I now know it is just balsa sheeted foam. Not even a spar inside it.

I also discovered the engine won't turn over. I cleaned it all up and it looks like either the crank is bent, or the bearings are shot. I was hoping the engine was OK and I would be able to use it again. So now it looks like I need to break it down too and see what has happened to it.

I know this is possible, but I really don't think so. At least if I had done the test flight, it may still have augered in, but I would have been able to say I flew it!

sydclement

My Feedback: (1)

Hi Maverick;
Very sorry to read about your Magnum crash. Just wondered
if you heard any humming noise when it started down?
The aileron linkage on some Magnum's is unsatisfactory for
200 MPH plane and there has been a few that went in from
aileron flutter.
I had to rebuild the aileron linkage on the one I am getting ready
now. I have seen tighter linkage on ARF trainers.

Syd

roywiglesworth

sorry for the loss but don't give up they are a great flying plane for the money i've got maybe 35 - 40 flights on mine and the only thing i know is they need to be just a little tail heavy compared to what the instrutions say. if you put too much throw in the ailerons
and had 50% expo after the stick is moved about half way the surface is going to make a big jump just something to think about
i usaly run about 35 and it feels good .if that did hapen i would say either radio failure or mechanical .i know we had a club member lose 3 planes before he could determan it was in the tx.and it was a stroke of luck we found it then.the magnum will fly if it is balanced right like its locked on a rail.if you can't find a mechanical failure i would chuck that rx no matter how good it ground checks.no sense in putting it in another plane and taking a chance when you compare the price of the plane to the price of a rx.

roy

maverick

My Feedback: (12)

No nothing!


The ailerons and servo were all rock solid even after the crash. There was a gash in the trailing edge of one of them no doubt from some sort of debris during the crash, but the linkages and servo were all OK.

maverick

My Feedback: (12)

Well mine was maybe just a little nose heavy if anything. From experience a tail heavy plane will get out of control much quicker than a nose heavy one. Being nose heavy it may have been harder to flare for landing, but we didn't even get that far.


Yes I know and not actually being the one on the sticks I have no way of knowing how much stick movement the pilot was using. It is possible he overcontrolled it not being used to expo.


Well from the post mortem I can almost say it wasn't mechanical, except for the elevator servo mounting plate which had come loose but I don't know whether this was pre or post crash.


It was a brand new Rx so I guess there could have been a problem with it even if it range checked on the ground OK.

This may be one of those ones that we never know the full story.

Flyboy Dave

My Feedback: (21)

....one word...."switch".

roywiglesworth

funny you said it was a new rx one of ourclub members had a bad
experence about 4 weeks ago with a rx it was in his x-cell copter
had something go out in it i think it was the 455 filter he sent it in for repair oh he was lucky he got it down just before it was going to hit .(he said he was shaking)in the mean time he ordered a brand new rx on the first or second flight after he had flown a 10 min or so flight he was about 10 ft. high 10 -15 ft. from him it just rolled over.when we helped him get all the parts gathered up we checked the range wasn't what i would call great but it was have of what he had before he had flown . i guess its hard to think of a new one having a problem but i guess after seeing this it looks very possible.

Cactus.

My Feedback: (1)

i've almost crashed getting out of trouble when my Outlaw gets out of it's -60% expo, but it does roll twice a second. i can't see an experianced pilot being thrown by this on the slower rolling magnum, it would just feel bad, having said that.. i did crash a mates Phantom coz it had a sluggish elevator with expo, i thought it was pulling up but it wasnt, i hit at a very shallow angle but found a rock
Like i said, a Magnum copy was like a bucking horse even with exactly the same throws and rates as his real one. he never found out why this was, just turned the rates down

Cyclic Hardover

My Feedback: (3)

Negative- expo is the way to go. If you go positive, all you have to do is breath on your stick and the plane will roll or do whatever so fast you will lose control.
* Those who do not have expo minimize the travel mechanically to the plane is not so touchy. With expo you could leave the throws as is and compensate with 15-20% negative


Anyways, a guy here has that magnum and no problems like what was desribed other than it has the glide ratio of a brick. If your engine quits, you better be in a position to land.

roywiglesworth

glide ratio if you have it just a fraction tail heavey is very good at least for a plane like this its not a kadet 40 or something like that
but i've lost a plug once and blown a coupler and still went once around the field before i set it down it was proberly 30 sec. from engine quit till touch down. the only reseason i said to keep it
just a little tail heavy i flew mine just on the front bal. piont and could never keep the nose up for a good flair i put about a 1/4 oz. of lead in the tail and it was all the differnce in a good landing and a scruffed up nose.

roy

flybike

A little tail heavy... Where do reccommend for the C.G. for my first flight? I just got the package today. I do not have a silicone coupler for the tuned pipe. I could order one, but it would take two weeks to get here. Any suggestions for an alternative? Some kind of hose, tubing, etc? Thanks, Hans

roywiglesworth

hi hans

roywiglesworth

i got mine about 135 - 140mm makes it glide a lot beter it touches down if you do it right maybe 5 mph you can get it to
stall just a couple of feet above the ground and it wil just pan cake .for the coupler got tired of blowing them apart made one out of a piece of alumnium tubing put cooper silocone on each end to seal it has worked fine ever since. i did cut about 3/4 in. off the header seem to help a little.the best prop i've tried so far and i've played with a bunch is a 8 x 9 if you'r looking for speed
it needs a good shove when launched with this prop but after about 30 seconds she'll completly unwind 9 x 9 will give it a litle better launch but top speed won't be as good. i would recmend
a piece of lite ply strip on the botom it will help protect it.

flybike

Thanks Roy, does the aluminum coupler create any radio interference? Would a copper pipe work as well? I am thinking of maybe 3/4 inch plumbing pipe here- What is the copper silicone compound you use? I have never had a tuned pipe here, so thanks for your help. Hans

ishu4u

My Feedback: (9)

got mine today and no instructions..i think i can pull it off anyway.
need the cg. as per above tells me distance but is that from LE at the fuse side measuring back? describe where the servo mounts are made to go pls. and the suggested thows for flight on surfaces......after 28 years building i think with the above info i got it covered.. and now i must fin a 8x9 prop somewhere...never used one with pitch larger than dia.
thanks
joe in ky

roywiglesworth

you might be able to use cooper but its so heavy no inever had any radio problems from doing this i made the fit very snug the piece i used was just a fraction too small inside diameter i took a dermel and sanded out till it would just fit with a little effort nut with out the cooper silocone it would leak you can get it at the auto supply store its made by permatex its used for hi temp gaskets. the bal.messurement is from where the front of the wing meet the fuse just messure back and put a small pencil mark on the fuse for reference.yeah some of these props get a little hard to pick up at hobby shops that don't have a big selection i'm getting ready to go thru the prop thing now with a new whiplash.
hope that might take less trial and error i think i went thru 8 or 9
before getting the 8 x 9 on the magnum.be sure you wash out the inside of the motor i didn't on mine didn't seem to hurt it but all that metal couldn't have been good for it wiped out 2 or 3 plugs until i realized what was happening. the only place i rember beefingin up was the wing block i epoxied a thick piece of maple under it i didn't use the blind nuts seen to many back out in flight
with out saftey wire i took and tapped the wood it self for 10-32 bolts also just to be safe i ran a servo screw on each side of the fuse in that block just to be sure. on the throws if you push the
surfaces close before you drop the ca in theres not a lot of travel so i set mine so i have full throw and then then set low rates about70% of the high you need the high at least on elevator for flare . the plane is out in the stepvan i'll go out side tomorrow and messure it to see what it is.
roy