Beaver Engine forward/baron stol kit performance issues

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Liberator24
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Beaver Engine forward/baron stol kit performance issues

#1 Post by Liberator24 » Wed Sep 27, 2017 7:34 am

Hello everyone,
I just started flying a beaver on wich the engine forward mod has been made on in combination with a baron stol. I keep reading about it, and everybody seem to love it... I don't at all. Maybe there's a problem with the installation they made on it? I know our mechanics put a weight in the tail because it was out of c.g. with with only a full tank and a pilot on board. My guess is that it probably doesn't help at all and it probably shouldn't be there...
The way it feels right now, even though it gets out the water pretty quick is that it doesn't climb well at all, even empty. The airspeed is pretty low too, even in cool days I get at most 100 mph, 95 most of the time with a good load on. It seems like it drags it ass quite a bit too, even with a bit of flaps on..

I feel like I like the good old untouched beaver quite a bit more.. not to impressed.

Any people on here know these mods pretty well and how much that weight in the tail could affect the performances?
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Re: Beaver Engine forward/baron stol kit performance issues

#2 Post by xsbank » Wed Sep 27, 2017 12:56 pm

Get them to check the W&B again. When the Firecats were first converted from Trackers, they had all the tailwheels still installed. They even installed an 8D start batter in the very back of the fuselage area. Years later, after stall margin indicators were installed, it turned out that the original mechanics made a mistake with the C of G calculation, the tail wheels were then removed and I believe the batteries were brought forward. All of these original mods had gone through Transport and they missed it too.

Don't take any of these mods for granted, if it feels wrong, it probably is.
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Re: Beaver Engine forward/baron stol kit performance issues

#3 Post by PilotDAR » Thu Sep 28, 2017 7:34 am

Liberator,

For my experience, W&B are the most error prone documents you'll find with respect to aircraft. In reviewing W&B for aircraft, I have found numerous, and serious errors. It may be a worthwhile exercise for you to go right back to the last weighing of the aircraft, and do the math from there forward, which may include W&B amendments (another place fore errors to sneak in).

I was the person who did the review of the W&B for the STC approval of the engine move STC back in 2003. The aircraft upon which I did my review was weighed (as I witnessed) and every loading case considered. The subject aircraft did not have the Barron STOL mod, so I can't speak to that. It is possible to load the aircraft out of limits (as it is with any aircraft), but with the engine move, its much more difficult to do, particularly on floats.

It has been authoritatively suggested that the Beaver was originally intended to be factory equipped with a Gypsy (Queen?) engine, which is long and slender. Apparently P&W offered DHC a great deal on R-985's, and the Beaver was changed to accommodate that engine, but perhaps the C of G ramifications of the different installation were not well thought out. Like many types, the world just learned to operate an aircraft which could have been a little better. A very wise and experienced pilot spent a quiet winter figuring how to make the best use of the Beaver's capacity, and realized that moving the engine forward was the solution. He was right.

I have a deidentified, sample W&B worksheet, applicable to the forward engine Beaver, from back in the day. I don't know how to post it here, but I'm happy to email it to someone, if they would like to PM me. It's only relevant for education, as its numbers are not applicable to any aircraft (now), but the overview is there.

I have never flown a Barron STOL Beaver, so cannot directly comment on that mod. However, in general, remember that any wing mod, particularly those which increase wing area, will affect the pitching moment of the wing as a whole. The pitching moment of the wing of an airplane is aerodynamically counteracted by the horizontal tail. How often have you seen a change to the H tail associated with a STOL modification? Robertson does on some of theirs, and I have required it on a few aircraft I have approved, but generally, these mods slip through as was. The aircraft may fly differently in not so obvious ways following modification, particularly multi mods.
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Re: Beaver Engine forward/baron stol kit performance issues

#4 Post by Rowdy » Thu Sep 28, 2017 9:30 am

Which baron STOL setup? The leading edge change, wing fences and drooped tips or the angle of incidence change? I've flown the firewall forward and the initial baron kit. But not combined. The baron kit is slow. 100mph seems about right. It came out of the water very well and climbed very well. The aircraft had seen a few alterations due to miscalculations in c of g and weighing and was spot on when I flew it. I was certainly a fan of the baron setup for tighter spots and shorter legs.

I always filled the rear tank when flying the machines with the firewall forward mod. Especially lightly loaded. They never seemed to feel like they were 'dragging ass'. The only time I noticed that was with a very rearward c of g on the aircraft that had the upgross kit. I also noticed those comments from folk who were overloading the airplane.

What else is done to the aircraft? Alternator and battery moved? Anything else that would alter c of g?
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Re: Beaver Engine forward/baron stol kit performance issues

#5 Post by Liberator24 » Thu Sep 28, 2017 12:56 pm

Rowdy,
It's got the leading edge changed, wing fences, wing tips dropped and the angle of incidence mod too. All of that in combination with the engine forward and the big was Edo floats (don't remember the number on the spot). Battery is moved forward and it's got the jabsco alternator kit. It's got the upgross kit for 5370 lbs too.
And everything I was saying on how it flies is with a normal load with would be around 1350 lbs on that plane with a full tank (I usually use the middle one, so does the other pilote here on the same plane here)
But all of that again is not really justifying the way it flies right now how I see it..
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Re: Beaver Engine forward/baron stol kit performance issues

#6 Post by Rowdy » Sun Oct 01, 2017 11:28 am

The angle change should make up for the speed drop with the rest of there Baron mods. Again, I've flown 'regular' beavers that would never, ever get out of the bloody white arc with a normal load! Some are really bent after what, 60+ years of service, and a lot of times they just aren't rigged right. One of the operators picked up a machine that was way out of whack. Spent a whole bunch of time rigging the floats and wings so that it would fly straight and gain a couple mph in cruise. Another one always needed a crack of flap in cruise. One particular machine would have a gentle turn to the left with your hands off the yoke no matter how many times it was re-rigged.

So with the battery forward and the firewall mod, it would certainly be a bit nose heavy. Not sure what else to tell you. They all seem to have their own quirks!
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Re: Beaver Engine forward/baron stol kit performance issues

#7 Post by lost in the north » Tue Oct 03, 2017 8:00 am

I am wondering if the wing angle mod, stol kit, gross weight increase, etc were flight tested and approved with the engine forward mod. I found out doing research for a few stc's I was doing to a Cessna that most of them were stand alone stc approvals.
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Re: Beaver Engine forward/baron stol kit performance issues

#8 Post by PilotDAR » Tue Oct 03, 2017 11:37 am

I found out doing research for a few stc's I was doing to a Cessna that most of them were stand alone stc approvals.
The "Ah Ha" moment. There's a paragraph at the bottom of every STC certificate to cover this, but it is rarely taken seriously.
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