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1/4 scale Piper PA-22 Tripacer Restoration

willsonman

Builder Extraordinare
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#1
Kicking off the next project here with a great subject and cool partners.

I picked this airplane up at the 2020 Lebanon swap meet for $50. I was on the hunt for a Tripacer for @earthsciteach but scored this beauty and is the perfect subject for some big flying as well as some really fun detailing in the cockpit area. My rough and dirty measurement gives about 86" span which makes it about 1/4 scale. A bit rough in spots but a solid airframe that was complete.
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The first major issue was that the airplane was clearly previously powered by a gas engine. While not an issue on the surface, the cowl was lacking... a second half. I was able to source a 1/4 scale cowl from Calvin's classic plans for as much as the airplane itself. It is a very stout part that looks the part and right size for this application. The oil cooler scoop will need to be added but that is a minor detail.
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The second major issue is the nose. My suspicion is that there was a fuel leak of some kind that soaked an unprotected joint in the nose gear assembly and the main wood strut member is loose from the fuselage. I cannot pull it out but it has about 1/16" play in it. It may just need some fresh epoxy injected into the joint but I want to remove the covering and do a full inspection of the member to see if it just needs to be entirely replaced.
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I want to also mention that this came with ALL servos. It was a mixed bag of servos, however, and some are names I've never heard of. Upon researching them, the servos seem adequate in torque spec with exception of the mini servos used for the flaps. I was also surprised at the size selection for push rods and servo horns for the model. They are not very robust and in the following shot you can clearly see this... including only ONE screw holding on the flap servo horn.
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This brings me to our first partner for the restoration. I'm very fortunate to have built a relationship with many folks in the industry. One of such people works for DU-BRO. This company is based and manufactures in the USA and has been a staple of the hobby for decades. They have been gracious enough to supply hardware for the restoration. Stout stuff that will bring a new and much longer life to this model. I like to keep in touch with my friends and as I shared this project with them they too were excited for it and made the offer with no solicitation from me.

The second partner for the project is again from another great company, Horizon Hobby. The entire airplane needs to be re-covered. The covering is a patchwork of old and brittle film covering that has clearly seen better days. While there are only a handful of minor holes, the condition of what lies beneath is questionable. Again, in an effort to give this model a new longer life, Horizon offered to supply me with some Oratex covering. In the past I've used Solartex covering for simulating my project's fabric coverings. This is no longer available and Oratex is just as good, if not better. It works great on tight corners and shrinks very evenly. It is a much more durable covering with a weight penalty that I think the size of this model can afford. It's paintable too so I can just cover with one color and detail it with some paint and masks.

Keeping in the spirit of the vintage nature of this particular model, I was also offered props from Master Airscrew. Many of you know how much I sing praises to Xoar for their efficient and stellar props but MA makes robust stuff that just works well. They too have been around for decades and I this offer was well-suited for the project. I'll be using one of their wood props that I'll paint to match the intended livery.

Power will come from a FT Monster Radial, a motor I've come to love, along with a FrSky Neuron 80A ESC for all the telemetry goodies. The plan is for a 6S setup where the batteries will either be installed from within the cockpit or under a hatch in the cowl.

Having NEVER done a restoration before, this is a GREAT project for me to learn and try new things. The vast majority of skills required here are from the fantastic projects that out own @Joker 53150 has posted on these very forums. I'm sure he will chime in when I'm missing something or stumble. I took a little time last night to have my first attempt at removing the covering. This technique I first observed from Jeff on one of his own many restoration projects. Rather than a heat gun, I decided to use the milder hair dryer so as to not entirely burn my fingers off. Gently heating the film and it lifts right off with minimal residue remaining on the wood.
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Lastly, I want to touch on the rationale for this project. @earthsciteach , Patrick, has been a dear friend for many years now. We met on this very forum and then met in-person at the very first Flite Fest. We have supported each other in the hobby and life, ups and downs, joys and tribulations, and so much more. He is a dear friend. I am building this model out to give to him and I want to make it very clear that there is NO expectation for any compensation on this project. He can chime in as to why this particular model is important to him as I don't think I could adequately relate his perspective. I will simply say, it is a major part of his aviation journey. This will be a small token of my friendship and I am a believer of doing good. Do unto others, as you would have them do unto you.
 

Joker 53150

Mmmmmmm, balsa.
Mentor
#2
"Do unto others, as you would have them do unto you." I thought it was "Do unto others, before they do unto you." My bad. :p

This will be a fun project to watch, especially because I don't have to do the work! Are the Tri Pacer wings fairly short, or could those wings be clipped a bit? Maybe it's just the camera angle, but the proportions look a bit like those of a 1/4 scale clipped wing Taylorcraft I've got.

Tearing off all the covering can be a chore, but on a project like this it really is the best way to make sure you find and repair all hidden "issues". Now that you've seen what the builder has done with the wings you know what to expect for interesting work elsewhere. I found this with my 1/3 scale Cessna project - as I kept removing covering, I kept finding more and more problems with the airframe. Good times...! :)
 

willsonman

Builder Extraordinare
Mentor
#3
Really the only issues I've discovered so far are minimal. The servo mounts are terrible. I can easily fix that. I thought for sure there would be shear webbing but turns out there is not! However, as you pointed out to me, in private, there are two sets of spars. The front ones are just aft of the sheeting at the leading edge and then another set toward the rear. In addition to the struts, that are quite stout, there is little need for them. The last issue I found was a loose cap strip at the wing root... easily tacked back in place by CA.

I'm not sure exactly because I purchased this from a guy who was selling it for a friend. I had ZERO information about the model. However, the full scale had a span of 29'3", or 351". that makes 1/4 scale at 87.75" Given my rough measuring of the span at around 86", if it's clipped, then it is not clipped by much!

I'll note that when the covering comes off, it does pull at the wood fibers a bit and makes a bit of a rough surface. I planned to sand everything down anyway so I'm not too concerned.

I'll pull out the servos and remove the control surfaces today so I can try to complete this wing by the end of the day.
 

Piotrsko

Well-known member
#4
Use heat to loosen the covering glue, an iron or heat gun but you know that. Nitrate dope thinner helps, BUT is hugely flammable. My technique was to paint it on, let dry fully then warm it up, back in the day.

Not clipped, 86 is about correct, the wing was set up for semi functioning "forever" struts (CASWPC joke there). I was the benevolent idiot of a chapter for a couple of years, owned and rebuilt an alaskan one, so what do you need to know about them?
 
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willsonman

Builder Extraordinare
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#5
I only need to know about this particular model. Plans would be great but I'm not sure I'll really get that far. Still, I'll figure it out if it cannot be identified. I'll have access to the airplane or pictures from Patrick when I need them.
 

Piotrsko

Well-known member
#6
Cool, replicating an existing. Wonder if ever met the plane.

Btw UNIVAIR has pictures of all the parts online like your cowl piece, but they should be super cub parts slightly modified.
 

Piotrsko

Well-known member
#12
Here's a little bit of light reading on the subject.
http://www.airbum.com/articles/ArticlePiperHighWings.html

TLDR: Long wing cubs like the J-3 had a 35' wingspan. In an initially cost-saving measure in '47, Piper removed a couple rib bays from each wing for the Piper Vagabond. The Tri-pacer was developed after the Vagabond and is therefore a short-wing cub.
actually, legend has it the wings were damaged sitting in stock, as was the prototype fuselage, clipped wing cubs were known to fly faster and be more robust, side by side seating was desirable, it's like a 6" increase. The Clipper was the sucessor and after the lawsuit with Panam became the Pacer gaining a rear seat, which after 3-4 years gained the nosewheel (Tripe) and the NEW improved O-320 instead of the 290. But what could I possibly know about this.

Nice wings, but I don't recall the upswept nose entry. Gonna have to find my left over rib
 
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rockyboy

Skill Collector
Mentor
#13
I'm a little late to the thread here, but love watching restorations! :love:

I'm sure you're going to add the sheer webbing, but to anyone else considering a restoration this can save your plane! Please don't repeat my mistake from my Elder 60 and leave the wing spars as they were from the original builder. After recovering with Oratex and a great paint job, I lost her on the second flight when the wings clapped. It's a very small weight gain for a huge strength increase, and well worth the time.
 

willsonman

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#14

I'm sure you're going to add the sheer webbing, but to anyone else considering a restoration this can save your plane!
I had really considered it but If you look carefully, there are 6 total spars. Three on the top and three on the bottom. This, combined with the struts that go from the bottom of the wing to the bottom of the fuselage, will be plenty strong. This airplane is not intended to do any crazy aerobatics. I'm confident that this conclusion, along with advice I've received from others, will be sufficient.
 

Joker 53150

Mmmmmmm, balsa.
Mentor
#15
Occasionally I'll cover a surface like that with a single piece of covering, although usually I do the bottom & top with separate pieces. In my opinion it makes dealing with the ends and edges easier, and I don't have to fight with too much covering sticking to itself. Personal preference.
 

willsonman

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#16
Occasionally I'll cover a surface like that with a single piece of covering, although usually I do the bottom & top with separate pieces. In my opinion it makes dealing with the ends and edges easier, and I don't have to fight with too much covering sticking to itself. Personal preference.
I absolutely agree. I usually do this approach for larger sections, like the wings and fuselage.
 

TooJung2Die

Well-known member
#17
I absolutely agree. I usually do this approach for larger sections, like the wings and fuselage.
Did you use one piece for the top and bottom to have one less seam? If so, wouldn't it be better to wrap the trailing edge and have the seam at the hinge line where it is less noticeable?
 

willsonman

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#18
I used one piece because it was simpler. I generally prefer my seams at the trailing edge as generally the air will be less turbulent compared to a gap between a control surface. Also, if the seam does start to break down, it is a LOT easier to hit it with the covering iron again to touch it up. A lot of seams give way, IMO, due to not being careful to thoroughly sealing the edges. When you tack and edge, it is just that... a tack. You really need to evenly seal the edges at the higher temperature BEFORE you shrink down the main surfaces. Some folks miss this step and then get frustrated or blame the adhesive of the covering when it's really their technique. I had this argument with a club mate... can you tell?

In terms of being noticed... seams are much less noticeable when they are on a corner... ANY corner. It is much less so when that corner is on the bottom side of the aircraft. Since I tend to focus on what is visibly seen and do that first, the ending seam ends up on the top side at the trailing edge. Still, after you have trimmed the covering and then sealed the edges at the higher temperature, that seam shrinks a bit and you REALLY have to look hard to see it.
 

Joker 53150

Mmmmmmm, balsa.
Mentor
#20
Did you use one piece for the top and bottom to have one less seam? If so, wouldn't it be better to wrap the trailing edge and have the seam at the hinge line where it is less noticeable?
If I did an aileron or flap like this with one piece, I'd probably put the seam at the front by the hinge, but for a slightly different reason. Yes, it's less visible, but for me the bigger advantage is that you can overlap the covering a bit more without it being visible. Again, just my personal preference.

I'm looking forward to seeing how the accent coloring goes on, painted or with a different color covering. I've got some planes that will likely end up with this covering now that Solartex is just a memory. :cry: