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Diagnosing a PHAT skybolt

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New Member
Sep 27, 2017
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Alright friends, long time lurker who now needs help.

I've been busy building an o360 Skybolt Delta for the last few years. That project is going well, though slower than planned, which is normal I suppose. But that's not the issue here.

I am looking at another Skybolt to potentially purchase, and play with while I keep building. While looking at this plane though, it seems to be a REALLY great plane, except that it is FAT.

This particular aircraft has been discussed here twice before:

First here...

Then Here....

I am trying to get to the bottom of WHY it is so fat, and I'm starting to scratch my head a bit. Somehow we are basically 200 pounds over. Here is what I know:

-Marquart Charger gear. Yes, I'm aware of the issues, but my discussion here is about weight. I know that this gear is heavier, but I have NOT heard anyone say a number. Does anyone have an estimate of exactly how much heavier this gear is?

-CS prop, IO360. The CS prop adds weight for sure.

-Factory fuselage, engine mount, and factory ribs. The ribs are plywood routed. This adds ~7lbs from what the book says.

-A fairly beefy avionics stack from what I can tell.

-A beautiful (depending on perspective) paint job that probably weighs in a bit.

-Sliding canopy, firebolt style, heavy.

Empty weight on this aircraft is 1350. All of the above adds up for sure, but I still feel like 1350 is heavier than even all of that can explain. Does this sound right to all of you guys? Where else might someone have snuck extra weight in? Where would you guys be looking for additional random firebolt mods that the original builder decided to swing in? I am quite familiar with the skybolt plans, (several years of building will do that) but I am NOT familiar with the firebolt at all. I don't know really where I should look for the likely mods. Perhaps it's time for me to finally read through all of those "improvements" in the newsletters?

I am really liking the plane, but the weight is bothersome, especially with the standard wing and the inverted V cabane having the lower gross weight. I don't really want to start a big discussion (another one...) here on whether or not you can safely fly over gross, that's another discussion for another time, but I WOULD like to try to get to the bottom of why she's so fat.

What do you guys think here? Where should I look? How outlandish is 1350 in the real world beyond the specs given by steen? I know the 980 is optimistic at best, and 1050-1150 seems to be more reasonable for a light build, but even 1150 would make me happy.

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