Step 2, Build Magnum!!

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Posted

I love the smell of MEK in the morning...

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Posted

Why do I have such a headache lately?..........

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Posted

Today we got the horizontal stabilizer mostly complete except for tape.

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Posted (edited)

Doug,

do you have a pic of the float attach points?

I’d like to add them...

Ron

Sorry to miss this Ron.

IMO, spreading the forces by widening the 'Z' strut float bracing has to be a good thing but, obviously, adding float brackets is best done before adding fabric. You can add forward or aft of the existing main gear brackets as desired. On my Mk-IV, I was going to replicate and add another bracket at the lower longeron tube cluster just aft of the rear main gear bracket. However, another Mk-IV float flyer showed me a set of removable brackets he made and used after covering and painting his plane.

It was a simple and ingenious solution that required no fuselage welding and only 3 small holes melted thru fabric with a soldering iron. It worked because on the Mk-IV there is a small vertical bolt bushing factory welded into that tubing cluster I mentioned earlier ( BTW, I never found an explanation for this bushing, only thing I came up with was an attach point for the optional ag spray equipment).

You can see the cluster and bushing in my bracket mock up pic. The removeable bracket plate bolts here from below, along with a 'C' clamp around a fuse tube on the side. If you look at a pic of the bracket plate with the mounting holes it will become clear. Note, there is also a tang and hole on the bracket bottom leg to attach flying wires.

HTH

If I was Barry, I would add a permanent bracket or bushing for removeable bracket at the same cluster on the Magnum. Due to the way the engine mount attaches to that fuselage, perhaps a simple tang extending down from the bolt for ski safety wire is quick and simple solution there

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Edited by dholly
P.S. - I have a drawing with measures in the shop somewhere I can dig up and post if anyone is interested.
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Posted

Doug,

I would be interested in the drawings for these. 

Thanks

Barry

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Posted

Today we covered the elevator, and got some great tips from Jim that made our day better and a nicer looking end product.

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Posted

Elevator is done, now on to the wings.  Great day thanks to my friend Dave!! Thanks to everyone for providing tips and advise along the way too, you know who you are!:)

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Posted

Nice Barry!  You nailed it!

Ron

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Posted

Another productive LONG day! Made it to stitching;)

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Posted

Today I learned stitching, all I can say is wow........lots of holes...........

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Posted

Today I finished stitching the left wing, poly brushed the stitch lines, marked for finish tapes and installed the inspection rings.  Poly brushed the finish tape areas (2coats) and the stitching and reinforcement tapes got 4 coats of ply brush. I have also decided on the right wing to do the stitching before covering with the top fabric to make that process easier. That cost me about 3 -4 hours extra labor. With the plywood leading edge, there is no way to stitch except using a fish hook style needle made from flexible wire. Pain in the butt!!!!  This will be my last post for a while as I will be repeating this process on the right wing for the next week or two.

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Posted

If you just do the bottom fabric and shrink it without the top fabric in place, you may put a bow into the wing.  I'm trying to remember how I grabbed the string the last time I ribstiched where I had an aluminum leading edge.   I'm thinking I pushed the string in with the back side of the needle, and then grabbed the sting though the other hole with a small wire with a hook on it.  Once I figured out how to do it, it wasn't that bad.   Nice progress on the other wing, looks good.   JImChuk

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Posted

Nice idea, that may work as well. I will let you know what I come up with. I was planning on just a light shrink, not enough to warp the wing.

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Posted

If you have the poly brush on the fabric and try to shrink it some more, you will make a real mess.  The poly brush will melt and stick to the iron.  JImChuk

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Posted

Agreed, probably just have to spent the time and do it they way I did this one.

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Posted

Barry,

I will look at the knot again, but I remember a certain diameter curve on the needle made it all work.  You had to run the thread through the next hole then back through that hole, through the rib lightening hole diagonally back up to the original set of holes...I’ll have to draw it out or something.

You obviously figured out a way to do it.  It ain’t easy but by knot 1000 it is reflexive!  Needles curved exactly right make it much easier.  I used a non standard 2” spacing, so even if I find my needles they wouldn’t help you.

Measure diagonally from the right hole on one line to the left hole on the next line down, that should be your diameter for your hoop, or curved needle. This is how you get the thread through the lightening hole.  Then use a straight needle (curved tip) to take the thread back down through the bottom left hole and up to the top left hole...make sense?

 

Ron

 

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Posted

Ron,

Thanks, that is exactly what I had to do. I used some wire to make a needle with the right curve, once the curve is right it worked pretty good.  I was hoping to come up with a quicker way, but I don't think there is one! I am sure I can do the next wing faster, I have had plenty of practice now!!  Thanks again for your input!

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Posted (edited)

One other thought.  Put on more inspection rings at potential places you will have to get to.  Pitot tube, strut brackets etc.  Don't cut them out till you need to get in there (at some point you will) but now is the time to put the rings on really easy at opposed to doing them later when its all nice paint and you have to get in there for some reason (joey is not the first person to blow the line off the pitot tube connection in the wing)  :lol: I think I ended up with 9 ring locations on each of my wings so I could get in and inspect things in the future if needed.  Another place to think about putting them in is where the drag tubes attach to spars.  The bent and flattened tubes have a known history of cracking and breaking so being able to get in there to look or possibly repair is kind of nice.

:BC:

 

Edited by akflyer
updated for clarity

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Posted

Yes, I ended up with 8 inspection rings.  Thanks for that good advise!!

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Posted (edited)

Seems like I usually needed 2 rings instead of 1 - One to put my hand thru and one to look thru to see what I am doing, or see how bad the bleeding is!   In Avschool we had to safety a turnbuckle inside of a pipe that we couldn't see thru - They had to sterilize mine from all the bleeding I did!  ;<)  I love the new turnbuckles with clips instead of safety wire!    EDMO

Edited by EDMO
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Posted

Decided to take a break from MEK to let my brain cells recuperate. I fabricated mounts for the new T-3 tail spring I will be using, can't wait to land with this and ABW's!!!

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Posted

Hey Barry,

on the airframes alaske website the T3 tail spring lists a weight of 5 Lbs....does that weight include the wheel???

I would love a T3 but am very limited in weight increase in the tail...

As it stands now my tailwheel spring (fibreglass) and wheel (6in) is at 3.3Lbs..

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Posted (edited)

Flywise,

I’ll let Barry comment on the weight, he bought the LSA version.  I’m sure that is 5# without the wheel though.

Also, be aware that even the LSA version only fits 1.5” and 1.75” Tailwheel receivers.  So unless you want to grind your new Tailwheel suspension, plan accordingly...

I bought the Piper Version and it is about the same weight as the Husky 3 leaf spring I had on it before.  For any other magnum owners or builders out there, the Piper 1500# coil over spring is way to stiff for the light tail loads of the Magnum...the lsa coil over spring of 1000# would have been fine, but you live and you learn!  It really lifted my tail up and maybe now I can taxi without doing the drunk swerve so I can see what is in front of me :BC:

 

Ron

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Edited by RDavidson
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Posted

Yes, the weight does NOT include the tail-wheel. My old spring and tail-wheel is 8.6 lbs. I will let you know the total weight after I get the right tail-wheel bolted on. I think it will be the same weight or a bit lighter.

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Posted

         Hi guys 

i have a few magnum question ,the kit I’m considering is unfinished .wings are built not covered and have not bin fit to the fuselage yet 

wash out- how is wash out built and checked after wards, is it adjustable after its built with the lift struts 

false ribs - wings were built for wing tip tanks , no tanks are installed so just  install ribs right ,

      any thoughts on bottom false ribs ?

wing tips-  or no wing tips 

grove gear-before covering what needs added to acomidate grove gear 

Thx rjg 

 

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