john josey

I think i have everything that i need.

smoknrv4

My Feedback: (11)

Ahhhhh, model airplane bootie, lovin' it.

john josey

I decided to buy everything new for it just to minimise any chance of failure, but it is nice working with new gear.

john josey

Carefully peeled back the bottom sheetingso that i couldreplace the supplied elevator snakes with sullivan ones.

john josey

I`ve also changed the supplied elevator snakes to servo connector, to ball links top and bottom of servo arm with M2 bolts, washers and nyloc nuts.

mk1spitfire

nice new gear, make sure that elevator tray is fixed

john josey

Yeah, it was just sat in place to take the picture, i`ve still to glue the plywood supports for the snakes.

vicman

My Feedback: (10)

I really like that idea![sm=thumbs_up.gif]

john josey

Thanks, it`s just for peace of mind. These things seem to have quite a high mortality rate, and i`m not sure if it`s down to pilot error or some sort of failure

vicman

My Feedback: (10)

From what I've read and seen first hand, most are lost from being too nose heavy and launching poorly. Do some searching in here and you will notice the CG needs to be a bit more rearward from what the instructions say.

john josey

From what i`ve read so far it seems to be anywherefrom the recommended 135toas far back as170mm, i was thinking around 150mm for the first flights ?

I tent to prefer a rearward CofG on most of my aircraft. (although i accept it`s not always a good thing)

vicman

My Feedback: (10)

Mine is at 150 and launches real fine with a Jett .50 and 9X8. As the days get a little warmer I'm going to experiment with some square and oversquare props.

john josey

Do you launch it yourself with an under arm throw ? i take it landing speed and flair is good at 150 ?

vicman

My Feedback: (10)

I have a buddy who always gives me a good launch. It has the glide ratio of a brick. As far as landing though it comes in and lands pretty good with high alpha..

MJD

My Feedback: (1)

While 150mm is farther back than instructed, as far as "rearward" versus "forward" CG's, it is not a rearward CG. It's a good place to start. Weston's point of view on this - I asked - was that the forward CG's really make them groove. Well.. yeah, that's what nose heavy aircraft do, but they are also a pig to flare for landing and there's more trim drag. I did a graphical neutral point and CG workup on the Magnum R, and was surprised to find out where a conventional stability margin of 10-15% puts the CG.. as I recall it was more like 190mm or a hair more. I've heard of them being flown at 190, but I would stick with 150, there are/were quite a few examples flying fine at 145-155.

- A 9-6 or 9-7 prop is a good choice for test flights, the 9-6 acts like a bit of a speed governor and pulls like a mule from the hand launch. Top speed is "limited" to around 120 or so, but it bops around nicely and flies about the same speed up, down, or horizontally. As I recall I never tried the 9-7, but others say it runs well too. A Sport-Jett .50 will run great on a 9-8, but the West .50 is timed higher and likes to be propped for a couple thousand more rpm. I eventually ran clipped APC 8.8 pylon props, in the 8.75-9.25 pitch range and 7.9-8.0" diameter.

Is that the .50, or the new .52 or whatever it is? My babbling pertains to the .50, not sure how the .52 differs if at all in timing.

- Take a peek at the wing straightness while you're going over it, make sure the tips aren't at different AoA or washed in at all.

- Your changes to the elevator linkage are wise, more than one was reported lost due to stock elevator linkage failure. I revamped mine for that reason.

- The CF-look graphics peel off easily. If you like them make sure the edges are sealed.

- Because there were visible gaps in the stock wing saddle, I protected the wing root with tape, removed the covering from the wing saddles, and built small fillets from epoxy fairing compound with the wing in place as a form. I never even painted them.. just used them as is. Lazy.

MJD

john josey

Interesting stuff for sure.

I`ll check the wings with an incidence meter just to be sure. The one thing i did notice was what can only be described as a slight 'bow' along the leading edge, although it seems to be the same on both sides.

The engine is the .52.I have 4 different sizes of prop to try 9x6, 9x7, 8x8 and 8x10. Obviously the 9x6 or 7 for the first flights though.

In over 30 years of building model aircraft this is my first ARTF, i usually avoid them if i can, just prefer to build my own i`m afraid.

It was my daughters birthday today, so nothing done on the magnum unfortunatly, but i dont see it taking more than a few days i would think.

vicman

My Feedback: (10)

Mind Mike's comments about the carbon looking covering! There has been more than one Magnum die from the covering coming off and disturbing the normal flow of air.

john josey

Yeah, it was my intention to go over all the covering seams with something like clearcote just in-case they lifted (not looking forward to it though, very tedious i would think)

Out of all the models i have to fly just now including the turbine powered f-16, the magnum is the one i`m most 'pumped' about getting flying. I had been toying with the idea since i first saw one at a trade show back in 2002 (only another week to wait i would think )

MJD

My Feedback: (1)

I think this depends a lot on the individual, but I found that the yellow colour scheme combined with swept flying surfaces made it a little more difficult to maintain visual orientation, at least until I got used to it. And the checkerboard, while eye catching at close range, turns into grey at distance. This is not an aircraft to test fly with grey cloud base or mediocre light. But it's not hard to fly, just not all that helpful I guess is the way to put it. It gets the crowd at the field pumped.. "fly the jet!" - I used to get that all the time.

MJD

john josey

I`m really looking forward to flying it. I`ll take your advice and pick a reasonable day weather wise though.

I would think the performance/£ or $ is pretty good value ?

mk1spitfire

Strength option consideration.

Under the front fusalage nose,(where the tank sits),I cut the bottom away in order that I could glass the from inside the side frames, to increase strength and also beef up where wing dowles lock into fuz.
Glue back in cut out belly block and re glass over the bottom, iron film on bottom on glass, this takes the landing knocks.

Improve wing dowles for twin type if single version.

Ditch the chequor film. Consider fluro colour?

Toughcoat those film edges to prevent lifting.

kmtranmd

My Feedback: (71)

I agree that the yellow and black may seem ok on the ground, but not that great in the air. I almost lost it in Oregon gray sky a couple times. I found that putting bright orange stripes on the leading edge area, about 3 inches wide made a big difference for me.
I like your elevator setup. I went with double servos due to paranoia and to help bring the cg back a bit. I dont' mind the 2 extra oz servo weight for peace of mind.
This thing needs plenty of elevator throw on landing. I have mine set up with about 1/2" full deflection and lots of expo, about 75% to smooth it out at full throttle.
You can check You tube on correct launching technique on this beast. But not difficult if your launcher is experienced. I don't know about self launching this thing, though. It does need a bit of up elevator feed and tends to roll one way until reaching flying speed.

john josey

Lot`s of good ideas/suggestions there guy`s.

I should have mentioned, but i had already glassed the tank bay to fuel proof it and used 1/2 oz cloth on the bottom and behind the wing dowel former, although i done it from the inside without taking the bottom off (what a pain).

This one is the two dowel set-up.

                                                            cheers
                                                                      john

john josey

This next comment may cause some concern from some, but i intend to fit a rudder to the magnum in the near future.

I will be installing the servo and control snake during the build, but i will be leaving the rudder off for the first few flights. I just know i will get bored if i dont add another dimention to it ! I know the airframe was designed for out 'n out speed but as far as i know nobody has done this before and nothing ventured nothing gained sort of thing. The first 'hint' of flutter and i wont hesitate to remove it.

For some reason i`m having trouble uploading the pictures from my phone tonight, i`ll keep trying.

mk1spitfire

Knife edge at 150, sweet