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Old Aug 18, 2009, 11:34 PM
Kenny- Really!
exciter900rr's Avatar
USA, CA, Cathedral City
Joined Jul 2007
809 Posts
Build Log
Restoring a Hobie Hawk back to it's former goodness..AGAIN!

Well, I've never done any kind of build thread or anything like it on here, and frankly don't know exactly if it should be under slope, thermal, or in this forum- I've chosen the "general" forum cause I think it's such a cool plane, and darn near a historic one in our sport. I don't think it would be all that invasive, but we'll see how it evolves.
So here goes-

I just acquired a hobie hawk that while in great shape, it has some issues....
It appears that it has remained untouched for what I would imagine would be the last 15 years or more. However one major issue it has is...... well, you guessed it.... a crooked tail.

Just for giggles I figured I would post up some pics, and "how I do it" which in this case, will be to rotate the tailpiece, and remove the "tail strengthener" LOL or in other words, a bondo'ed/fiberglassed boat anchor/fin extension that was added to reinforce the characteristically weak tail. I have begun removing the covering to inspect the airframe for further damage before I re cover the plane for a fun fly in less than a month.
I'll try to slow down when it comes time to re cover it, as I usually start, and then by the time I think about taking pics, I'm done and two days have passed... lol I enjoy reading build threads, and have decided (with this project) to see if I have what it takes to actually produce something close to one. Hopefully I don't flop at it-
I'll be doing this over the next couple of weeks, (it has to be flyable by Sep.13th) so I'll update it as often as possible. Heck- Maybe just one thing I do here will help someone fix another plane. Who knows.....
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Last edited by exciter900rr; Nov 23, 2011 at 06:15 PM. Reason: Resurrection for a new bird
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Old Aug 19, 2009, 02:11 PM
planepainter
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Mt. Juliet, TN
Joined Sep 2008
2,004 Posts
Hello Exciter. Looks like you made a good snag. I am sure it will be more than worth the effort it takes to restore it. Look forward to the log. I don't know if you have seen it but there is another thread near this one about refurbing an old Aquila where he deals with a crooked tail and gets some great suggestions. BTW, I used to exhibit my paintings at the spring and fall outdoor art shows there in PS. Great times. PP.
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Old Aug 19, 2009, 02:19 PM
Herk
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Virginia USA
Joined Jun 2007
1,636 Posts
Will look forward to clearer pictures.

The plane may have some modifications to improve it's handling qualities. It's hard to tell with that photo because of the black color and the lack of contrast.

That dorsal fin could have been put on there to reduce the Hawk's notorious dutch roll tendency - though you'd think the guy would have tried to keep it light, if that was his intention.
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Old Aug 19, 2009, 02:45 PM
Kenny- Really!
exciter900rr's Avatar
USA, CA, Cathedral City
Joined Jul 2007
809 Posts
Thanks for the replies already guys!
I actually like the way the stock hobie flies- the "hobie roll" is what it's all about, and keeping the plane true to it's roots is the goal. It's gonna be fun!
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Old Aug 19, 2009, 07:21 PM
Herk
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Virginia USA
Joined Jun 2007
1,636 Posts
Quote:
Originally Posted by exciter900rr
Thanks for the replies already guys!
I actually like the way the stock hobie flies- the "hobie roll" is what it's all about, and keeping the plane true to it's roots is the goal. It's gonna be fun!
True to its roots - Yep we all know what they are
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Old Aug 19, 2009, 09:10 PM
Kenny- Really!
exciter900rr's Avatar
USA, CA, Cathedral City
Joined Jul 2007
809 Posts
Quote:
Originally Posted by HerkS
True to its roots - Yep we all know what they are
NICE!
Honestly, the only time my last one made me feel like that was a crosswind winch launch- But I have never had issues per-se maintaining control of it- I just kinda like that "yaw walky thingy" that it does so well- kind of like a lost dog wandering around or something- lol But never out of control. I suppose I'll shoot some progress pics from last night, along with some detail of the tail that I'm preparing to change back to "normal".....
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Old Aug 19, 2009, 10:42 PM
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Exciter:

I, too have an old Hobie, refinished in all blue. I had stored it a while, and opened it to find the trailing edge of one wing all buckled. So, recovery time, I suppose.

I had some thrilling flights, flying at the sod farm on the prairie, out east of Albuquerque.

Yours, Greg
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Old Aug 19, 2009, 10:45 PM
Kenny- Really!
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USA, CA, Cathedral City
Joined Jul 2007
809 Posts
Ok-
Stripped one wing, and the tail group. to the point where you need to:

-Make a nice big "drink"
-Turn on the tv/radio for background noise and an occasional reference of time
-Get situated and comfy at a workbench
-Have lots of sharp #11's on standby
-Be ready to test your patience

I begin stripping the covering by slicing a couple open bays open, and working the covering loose and trying to peel as big a piece off of the airframe. Once I have all I can get off by hand, then this is where the fun begins.

There are a couple of things that are unique to the plane- you don't want to use too much heat due to the dark covering material combined with the 1/64" ply sheeting, and also being a foam core. In the case of the dark color (black) the pigment would be left behind in spots and excessive sanding would quickly burn through the first ply. Since I plan on using transparent covering over the open bays, Neatness underneath counts.
Also some people use acetone after heating the covering off- No no here as well cause it will melt the foam. So we will use patience, and time and get those sharp x-acto blades out and peel off ALL of the tiny bits. It's kinda like cutting your hair one hair at a time. Eventually it gets done, and looks nice, and thankfully, Monokote doesn't grow back!
Soooooo... This is what I will be doing for a couple of days.

Also, some pics of progress- and that tail fin thingy that will be cut off as soon as the surfaces are clean and neat.
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Old Aug 19, 2009, 10:48 PM
Kenny- Really!
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USA, CA, Cathedral City
Joined Jul 2007
809 Posts
Quote:
Originally Posted by glidermang
Exciter:

I, too have an old Hobie, refinished in all blue. I had stored it a while, and opened it to find the trailing edge of one wing all buckled. So, recovery time, I suppose.

I had some thrilling flights, flying at the sod farm on the prairie, out east of Albuquerque.

Yours, Greg
Mang- That stinks! Did something fall on it or something? I have fixed one before that had the wings folded up on. Man that was tough! but possible! Wish I had a better picture of that one, but a nice angle...
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Old Aug 21, 2009, 06:11 PM
Kenny- Really!
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USA, CA, Cathedral City
Joined Jul 2007
809 Posts
Allllllllllllllrighty then......
That was THE MOST TENACIOUS COVERING that I have ever stripped off of an airframe...

But it's over and done with now- I now have a nice idea of what repairs and joints to re-glue to make her like new again- I won't be doing any mods or anything like that, just a simple restoration so to speak.

Here's the progress pics, and now I have to get into that vertical stab and see if there was a break or something that warranted that sub fin thingy.

Also, I replaced the wing rod with a stainless unit I found at ace hardware- 5/16"... Better than sleeving 1/4" steel with brass to get there. all the other pins were replaced new because they were bent pretty good, and I'm pleased to find that the stab isn't as bad as I thought. It's a touch loose for my taste, so I'll drill it out, and re bush it adjusting the angle of the stab relative to the wings to make them parallel.
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Old Aug 22, 2009, 02:21 AM
Kenny- Really!
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USA, CA, Cathedral City
Joined Jul 2007
809 Posts
The fiance and I are off to the San Diego Zoo tomorrow, so I'll do my best to post some pics in the morning before we leave- I have got the fuse stripped clean of the black paint, after uncovering the sub fin to find it was actually added for aesthetics! (or handling??) There was no visible damage under the fin, just a few bumps and bruises that had been fixed before the black paint job. she's primed now for paint, and now that I feel comfortable touching her again, I'll do my best to drill and re-bush the horiz stab-..... I think.....

I'm weighing the pro's and con's of doing the stab, and trying to gauge weather or not it's worth it for 1/4" or not..... you know- the possibility of damage? sticky elevator is not something I want to risk, but I still have a few ideas.....
Why not do it as it's all uncovered and unpainted right now- no risk no gain!
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Old Aug 22, 2009, 02:40 AM
Kenny- Really!
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USA, CA, Cathedral City
Joined Jul 2007
809 Posts
OK- I decided I wouldn't have time to put them up in the morning..... I said this was gonna happen quick right? LOL Descriptions are mostly in the pic titles- But,



I first plunged into the "mess" in the tail with a dremel and sanding wheel to identify the actual vertical stab-slowly advancing towards the general area until I saw a different paint color- (vert stab) I then followed it down to the boom, and essentially connected the dots- Sand the filler material, not the base material- I'm just so happy I don't have to re-repair the tail!!!!!

I also cored out some of the foam behind the break in the rudder and let in a piece of alder hardwood for strength- Worked VERY well!

Pics-
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Old Aug 22, 2009, 03:08 AM
Balsa breaks better
Thermaler's Avatar
Buchanan Mi
Joined Apr 2005
2,066 Posts
This is cool!!! I am just about to the cosmetic stage of rehabing an Aquila XL looking ahead to the Hobie I have that is in need of a bit of TLC.
I was going to do a search but not now.
Show me the way to bringing mine back to life.

Joe
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Old Aug 22, 2009, 03:17 AM
Kenny- Really!
exciter900rr's Avatar
USA, CA, Cathedral City
Joined Jul 2007
809 Posts
Thanks for the compliment, Joe!

I tell you what- I just found out on a "Hobie hawk" website, that the dorsal fin was a widely accepted mod to help with yaw stability- And I just ground it off!
But seriously- They have a weird way that they track, and it's just dandy with me- I'd rather it look like a Hobie than a submarine or something with that god awful fin on it-

I'm not doing much to it, other than restoring it- and it was in decent shape to start with- I know it might be a cheesy thread, but I just wanted to see what I'd come up with on something fairly straightforward...
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Old Aug 22, 2009, 08:51 AM
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United States, WI, Elm Grove
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Nice job so far. Keep the pics coming.

Jim
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