Stick and Tissue Forum
https://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl
How to build model airplanes >> Wrecks and Repairs >> Guillows Skyraider Rebuild
https://www.stickandtissue.com/cgi-bin/yabb2/YaBB.pl?num=1548044546

Message started by MKelly on Jan 20th, 2019 at 10:22pm

Title: Guillows Skyraider Rebuild
Post by MKelly on Jan 20th, 2019 at 10:22pm
I've got a Guillows 900-series Skyraider that I built in 1995 and have a real soft spot for - it was the first rubber-powered model I built that really wanted to fly.  After surviving half a dozen moves over a 20-year period I put it back in flying condition in 2016, and with the benefit of FAC coaching it became my first model to stay up over a minute. 

In 2017 I took it to WESTFAC and flew it in Modern Military.  It put up decent flights the first and second flights, then I broke a motor winding for the third flight.  Blew out the tissue on both sides of the fuselage, but the model seemed otherwise intact so I put in a fresh motor and wound it again.  As I walked out to launch, there was a big crunch as the lower left longeron gave way.  I figured I had nothing to lose, so I tossed the airplane up anyway and was rewarded with a 44-second flight!

At that point I decided to retire the model as it had been repaired and patched numerous times, and I figured it had probably earned a rest.  Pics below show how it's sat for the last 15 months.
0120_Skyraider_Damage_Left_Side.JPG (343 KB | 13 )
0120_Skyraider_Left_Side_Closeup.JPG (260 KB | 12 )
0120_Skyraider_Damage_Right_Side.JPG (298 KB | 13 )
0120_Skyraider_Damage_Underside.JPG (266 KB | 12 )

Title: Re: Guillows Skyraider Rebuild
Post by MKelly on Jan 20th, 2019 at 10:33pm
This weekend I've taken a break from building a 26" span Wicko GM-1 from plans off Outerzone to do some flying and make various minor repairs on my models. After fixing some damage to the Waco, pulling a broken motor out of the Citabria and patching a leading edge break on the Navion I picked the Skyraider up off the shelf and felt inspired to get it back in the air.

First thing was to pull off the tissue and see what the structure looked like.  The lower left side was fragmented, and didn't look like it could be glued back together resulting in any kind of solid structure.

My solution was to build a crutch for the lower fuselage, glue that in place, then replace the sheeting as required to get a smooth surface for tissue.  While I was in there I moved the peg mount forward one bay, which will pretty much center the motor on the cg and should reduce or eliminate the motor binding up at the rear (which had sometimes been a problem on this model).  It should also offset most of the weight of the repairs by moving the motor weight forward and allowing me to eliminate some noseweight.

I got all the structural work done today.  Once I had things in place I went back and judiciously carved out some of the side sheeting aft of the peg to try to get a bit more weight out of the aft end.  The fuselage feels very solid and there's still a nice bit of structure right where you grab the model for launching.

Mike
0120_Skyraider_Damage_Tissue_Removed.JPG (334 KB | 28 )
0120_Skyraider_Repair_Lower_Crutch.JPG (270 KB | 25 )
0120_Skyraider_Repair_New_Peg_Location.JPG (312 KB | 23 )
0120_Skyraider_Repair_Trimmed_and_Sanded.JPG (279 KB | 26 )
0119_Skyraider_Repair_Right_Side_Trimmed_and_Sanded.JPG (333 KB | 21 )

Title: Re: Guillows Skyraider Rebuild
Post by Huey v77 on Jan 20th, 2019 at 10:42pm
Neat. AD's were known to take a lot of damage and make it back.

Title: Re: Guillows Skyraider Rebuild
Post by Sky9pilot on Jan 20th, 2019 at 11:46pm
Nice job on the repair!! She should really perform for you now!
Tom

Title: Re: Guillows Skyraider Rebuild
Post by pb_guy on Jan 21st, 2019 at 10:16am
That was a lot of damage to overcome. I would have been tempted to rebuild the whole thing. Great repair.
ian

Title: Re: Guillows Skyraider Rebuild
Post by MKelly on Jan 22nd, 2019 at 9:10pm
Thanks guys.  I dug through the tissue drawer and found some Guillows grey tissue (might have been left over from this model, who knows).  Although far from fresh it went on fine, although the patch looks pretty ratty once the dope is on as you can see all the underlying wood and partially-sanded tissue.  No worries, a quick spray of dark blue (from the same bottle used to paint the model when built in 1995).  I'm a preservationist, not a hoarder, thank you very much!

I opened up the rear of the stab slot a bit as I anticipate having to decrease stab incidence.  I ran the tail volume calculations on the model and it looks like I should be able to move the cg back around 1/4" as the model has a fairly generous stab (TVo-.65).  The model always was a bit loopy when flown fast, this should help tame that, as well as reducing downthrust a bit.

In the background you can see evidence of what has turned into a fleet-wide maintenance spree. 

Cheers,

Mike
0121_Tissue_Patched_Right_Front.JPG (231 KB | 27 )
0121_Tissue_Patched_Bottom_Right.JPG (261 KB | 22 )
0121_Tissue_Patched_and_Doped_Right_Side.JPG (312 KB | 25 )
0122_Fuselage_Repainted_Right_Side.JPG (318 KB | 27 )
0122_Fuselage_Repainted_Left_Front.JPG (225 KB | 28 )
0122_Fuselage_Repainted_Bottom_Right.JPG (351 KB | 17 )

Title: Re: Guillows Skyraider Rebuild
Post by MKelly on Jan 25th, 2019 at 2:33pm
I peeled off all the old bond paper markings and replaced them with printed tissue markings.  I used my typical technique of coloring the back with a white pencil to keep the dark blue from showing through the white markings.

I added the AD-4N cooling scoop and an antenna on top the rear fuselage and replaced the wing cannons to finish off the detailing.  Last step was to replace all the clay and field thrust shims with a wedge of balsa to hold the thrust angle and keep the noseblock firmly fixed during flight.

Empty weight is 24.5g - I didn't weigh it before so I don't really know whether I added or subtracted weight from it.  Right now it is very slightly nose-heavy with no added ballast (and no motor).  The motor should be pretty well centered on the cg with the new peg location, so hopefully very little ballast will be needed.

The group picture shows all the models I worked on this week - they're all back to flight-ready, looking forward to some winter flying sessions.

Mike
0124_Tissue_Markings.JPG (248 KB | 29 )
0125_Rebuild_Complete_Right_Front.JPG (282 KB | 19 )
0125_Rebuild_Complete_Left_Side.JPG (346 KB | 25 )
0125_Rebuild_Complete_Right_Rear.JPG (294 KB | 26 )
0125_Repairs_and_Rebuilds_Jan_2019.JPG (305 KB | 30 )

Title: Re: Guillows Skyraider Rebuild
Post by Sky9pilot on Jan 25th, 2019 at 7:00pm
WoW Mike, your new markings really make her pop!  Great job on the whole squadron! [smiley=thumbsup.gif]

Title: Re: Guillows Skyraider Rebuild
Post by pb_guy on Jan 25th, 2019 at 11:54pm
Good as new! Invisible repair.
ian

Title: Re: Guillows Skyraider Rebuild
Post by MKelly on Jan 26th, 2019 at 10:41am
Thanks!  Now to make a blast tube that fits through the noseblock so I don't have to make this repair again.

Mike

Title: Re: Guillows Skyraider Rebuild
Post by bigrip74 on Jan 27th, 2019 at 9:53am
Mike, I am very interested in seeing your blast tube application since I have yet to try one.

Bob

Title: Re: Guillows Skyraider Rebuild
Post by New Builder on Jan 27th, 2019 at 12:44pm
Mike - Beautiful repair and another reason for keeping the plans after the model is completed. I was wondering how many people kept the plans after the build was complete.
Mike

Title: Re: Guillows Skyraider Rebuild
Post by MKelly on Jan 28th, 2019 at 10:16am
Bob,

I made a couple new blast tubes (5/8" dia and 1/2" dia) this morning for my smaller models (like the Skyraider) - here's some pics.  I used thinwall rigid aquarium tubing, which you can get in a variety of diameters from Amazon or many other online suppliers.  File a notch at the peg end of the tube so it can slide over the motor peg and be turned to stay in place (direction of the slot matters, as you want the tube to stay on the peg while the rubber is rotating within it, see picture).  Put the tube in the model and latch it on the peg, then cut it to length so that you have enough sticking out the nose to hold onto while installing or removing the tube.

The wire hook is used to feed the unwound motor through the tube prior to inserting the tube in the model, and to hold the wound motor while sliding the tube out of the model.


Mike, thanks for the kind words.  I've kept I think every plan I've built from, both for circumstances like this and in case I ever decide to build another one.  Or just to look at from time to time.  I might be a bit of a hoarder...

Cheers,

Mike
0128_New_Blast_Tubes.JPG (356 KB | 24 )
0128_Blast_Tube_Peg_End.JPG (253 KB | 24 )
0128_Blast_Tube_Fitted_For_Winding.JPG (322 KB | 28 )

Title: Re: Guillows Skyraider Rebuild
Post by 93rdLiberator on Feb 27th, 2019 at 12:58am
Great job, Mike.  I'm glad Calvin is still in there too!

Best shot of a blast tube too so thanks for that!!

Dan

Title: Re: Guillows Skyraider Rebuild
Post by bigrip74 on Feb 27th, 2019 at 11:40am

93rdLiberator wrote on Feb 27th, 2019 at 12:58am:
Great job, Mike.  I'm glad Calvin is still in there too!

Best shot of a blast tube too so thanks for that!!

Dan


"DITTO"

Bob

Title: Re: Guillows Skyraider Rebuild
Post by MKelly on Feb 27th, 2019 at 8:58pm
Thanks Dan and Bob.  Hope to get a chance to fly it maybe this Friday.  We've had some decent days here but they haven't lined up with my availability - seems like if I'm free it's wet or windy...  This Friday is looking promising.

Bob, the Cloud Climbers and Lone Star Squadron are having some meets in May and June at the Hamilton Municipal Airport - pretty close for you Austin folks.  Hope to see you there.

Cheers,

Mike

Stick and Tissue Forum » Powered by YaBB 2.5 AE!
YaBB Forum Software © 2000-2010. All Rights Reserved.