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Bushwacker 2.0 a.k.a. Cub Killer

Mauleguy

MEMBER
Bushwacker rebuild is finally complete, still working the bugs out so not completely satisfied yet. Here are some of the details of the rebuild:
Extended the 33'8 wing to 36' (added 12" to each spar and used the Dakota wing tips)
Shortened the flaps from 120" to 114"
Extended the ailerons from 60" to 77" (best flying Experimental Maule ever for roll control)
Went from Lycoming O-360 (180hp) to Lycoming IO-360 (200hp)
Went from 90" fixed pitch to 84" constant speed propeller
Added the tip tanks back in for a total of 67 gallons of fuel from the original 44 gallons.
Changed the yoke side by side seating to center line seating with stick for pilot and cub style heal brakes and rudder peddles, moved the rear sling seat forward 6"
Changed the angle of incidence of wing attach fittings from 1 11/16" to 3 1/8" (made horizontal ground adjustable to get the angle correct after initial testing)
Made cub style cowling and custom dynafocal engine mount shortened and lowered
Weight before rebuild 1325 with empty CG at 12.6 weight after rebuild 1359 with empty CG at 13.0 (gross weight of 2500)
Simplified instrument panel and lowered top by around 3"
Made the extended baggage flat with the rest of the baggage area so there is around 7 feet of flat floor from the back of the cub style seat to the back of the baggage.

I only have a few hours in it but based on what I have seen so far it looks like it will cruise around 117 mph at 2350 rpm at sea level (not sure how much power I am putting to it because my Dynon is out of it for repair) but it is not firewalled at that speed. I would guess I am probably at 25" of manifold pressure.
it will land at around 35 mph GPS and the visibility over the nose is better then my cub.

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So that's the angle valve 360 with the flat valve covers?
Considering the wing extension and the general size of the machine, the empty weight is pretty impressive, and the slight shift aft can only make it a touch lighter on the controls. I want a ride. No, actually I want to FLY it !!
 
One of the few planes I’ve considered building my own version of. Have watched you put the original thru its paces more hours than I can count. Would love to see some video of the thing flying some STOL .
Congrats on getting it back up.
 
Thank you for the specs. I’m curious re your prop. How did you select the length? Who’s prop—Hartzell, Whirl Wind, ?

Again, thank you!
 
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So yes it is an angle valve IO-360 Lycoming and Hartzell compact propeller. Tom, Laurie and Greg at Western Propeller put it together with my type of flying in mind. I told them I wanted it to turn up to at least 2700 rpm on takeoff which it does I am still playing a little bit with that and until I get the Dynon back I probably won't have it set where I want. The climb out feels really strong with this prop. I have not heard from the ground of course but I guess it is pretty loud which I did not particularly want.
 
I went with a Garmin G-5 (very cool, love it), Dynon EMS-D10 (so far I am regretting that) and a Garmin 660 aera, MGL V6 com.

Here is the down side with the Dynon, back light quits while I am changing sensor settings on the ground before first flight. I send it back overnight and they don't check it in for 3 days. They say they normally turn repairs around in 10 business days. Well it looks like they are going to take at least 10 business days to do that so I am without most instruments for engine. I am using a oil pressure gauge that I mounted in place of the Dynon and a hand held tach that I shine through the windscreen. I am not sure if I will ever do a all in one engine monitor again. In fact I am pretty sure I won't.
 
I'm impressed that you were able to make all those changes from the original and still keep the weight down. Awesome!

MTV
 
If it's loud, it must be the exhaust system. An 84" prop turning 2700 RPM has a tip speed of 675 MPH. The speed of sound is something like 760 MPH @ sea level/standard day.
I have the FAD Hotrod on my 320 so we're kinda in the same boat as noise goes.
 
Looks like plenty of elbow room! That center seat is so hardcore......, that says more them most of your other mods as to how you plan to use it. For a tandem plane pilot, I'd feel lost in that thing, like I had shrunk.
 
Very nice for someone just wanting to go for a flight alone and land where others can not!! The center front seat is interesting, though the stick would be a great deal better than yoke.

Coming north this spring? would love to check it out in person.
 
That is some serious cargo space. Center seat is something we don't see every day.
Glad your custom propeller makes your engine scream.

We need some video please!
 
The new plane looks great. I can’t wait to see it in action. Great color choice as well!

A couple of questions...

So it is a Cub wing? Stock or Dakota, Javron, etc?

Is this the original Bushwhacker fuselage(M5) reworked and modified? Or did you build a whole new fuselage from scratch?

Lastly, what covering system did you use?

Joe
 
They are the wings that were on Bushwacker before the accident, started life as the biggest wing Maule ever built 33'8". I needed to reskin both of them after the accident and since I was already in them and always wanted just a little more length I decided to do a spar splice and add a foot. I also never liked how the Maule wing tin canned so easy so I went with .025 skin on both sides vs .020 on the top and .025 on the bottom like Maule does it. I wanted it to be more sporty in all kinds of conditions so this allowed me almost 12" more aileron, I did not feel that was good enough so I shortened the double slotted flaps by another 6". This wing originally had 126" flaps and 54" ailerons which really sucked in windy conditions. I had already shortened them by 6" when I went to the double slotted flaps. With these changes it really handles like I have always wanted for roll control.

I used stits with aerothane for the covering and paint.

It is a two blade Hartzell, experimental propeller that was built with something like 8.5 degrees and 38 degrees at the pitch stops. Not really sure how that compares to my fixed pitch 90" which was pitched at 33 but it seems to work pretty well right off the bat. It is amazing feeling the 200hp at 2700 rpm with the constant speed vs the 180 hp at 2450 with the fixed pitch. In reality the 2450 was probably around 160 hp with the 10.5 to 1 pistons.

The fuselage was bare tubing nothing added except the gear attach, engine attach, strut attach. It had no pulleys, no sheet metal and no wing attach. Made it easy to make it the way I wanted but was a lot of work. The old fuselage was not used.
 
If it's loud, it must be the exhaust system. An 84" prop turning 2700 RPM has a tip speed of 675 MPH. The speed of sound is something like 760 MPH @ sea level/standard day......

84" at 2700 on a standard 59 degree day = .88 mach.
That's the bottom end of the .88-.92 "sweet spot" according to Pponk's tip speed calculator.
As far as loud goes, when I pull back the MP on my C180 after takeoff but leave the prop alone,
it gets a lot quieter inside the airplane.
Is that just less exhaust noise, or doe the fact that there's a lot less oomph behind the 2600 rpm make a difference too?
 
I don't think propeller AOA would have much -if any- effect unless maybe you were right at the edge of sonic, and then that's just speculation / imagination on my part.
 
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Coming from someone who likes turning the molecule from the ground to as much noise as possible :evil: . It’s normally the high RPM with flat pitch that sends the neighbors 15 miles away the message that your up!
 
Way to go Greg! It looks like you put a lot of thought into build. I like that you did away with the lower half of the instrument panel. What did you make your doors out of? What did you do for an interior? What about starter, alternator, and battery? I would love to hear how it flys with two guys in the back seat and a couple of back packs.
Isaac
 
Yeah those two bars, one on each side of instrument panel make great handles for pulling yourself up and in when on 35" ABW. I used the stock door frames modified for angle of incidence change with no center bar and covered them in .060 hardcoated polycarbonate, super lightweight. I used the camper type shock to hold them open they are hinged from the top and the latch is in the bottom (just a single pin that drops in the jam). Interior is .020 aluminum and powdercoated with honeycomb composite floor boards. I used Oratex above the waterline to keep from poking the outer fabric with objects inside. BNC starter, BNC 20 amp accessory mount alternator, PC-680 battery. I machined the magnesium sump for a forward facing fuel servo, keeps it real simple and ram air, I made the airbox attach to the bracket air filter (very short) with a door for alternate air. Still testing with it light, will load it up very shortly and see how well it does.
 
Greg
Try an EarthX battery and save another 8-10 lbs. Cranks faster than any Odyssey!

Lou
 
I would like to use earth x but I am worried about having it inside the cockpit. I currently have it mounted on the firewall cockpit side. I was reading on EarthX web site they don't recommend having it inside.
 
I would like to use earth x but I am worried about having it inside the cockpit. I currently have it mounted on the firewall cockpit side. I was reading on EarthX web site they don't recommend having it inside.

Mine’s mounted on the firewall, cabin side. Been there for a couple of years, no issues.
 
Mauleguy
Where did you get your .060 hardcoated polycarbonate ? I have not been able to find the Hardcoat in .060.
Thanks Doug
 
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