Looking at an SA700- Acroduster One - any hints on special things to look for during inspection?

Discussion in 'Starduster' started by Jonas Larsson, Jun 13, 2018 at 6:38 AM.

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  1. Jun 13, 2018 at 6:38 AM #1

    Jonas Larsson

    Jonas Larsson

    Jonas Larsson

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    Hello gentlemen, i am about to look at an SA-700 Acroduster One and hopefully buy it if all things end up well. There are not to many threads about them in this or other forums. If anyone has any knowledge you would like to share that would be very much appriciated.

    Best regards Jonas
     
  2. Jun 15, 2018 at 10:46 PM #2

    IanJ

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    Probably the generic "Buying a used airplane" advice will serve you well: get an independent pre-buy inspection from an A&P who has some familiarity with rag and tube, etc. I'm afraid I don't know much about the Acroduster, but that includes that I can't recall any negative things to look out for. Being at least loosely based on the Starduster, it would be worth contacting @Dave Baxter directly, as he is the undisputed master of Starduster information, and he's usually quite happy to help folks out with this kind of question. I think that they're pretty different planes (Starduster vs. Acroduster) once you get down to details, so the detailed problems found on the SD, like the landing gear location/length, are probably not useful things to look for on the AD.

    Good luck! I hope it turns out to be awesome, and post some pictures, even if you decide against buying it. We always like to see new planes. Pictures may also spur someone's memory, and you might get some unexpected info about the particular plane you're looking at.
     
  3. Jun 16, 2018 at 1:26 AM #3

    bipedream

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    Make sure all of the paperwork for the airframe and engine is there and complete
    Get the FAA data CD on the airplane.

    Take looks of pictures on the initial look and take a look at them when you get home.

    There aren't many of them out there so type specific advice will be tough to come by.
     
  4. Jun 16, 2018 at 5:22 AM #4

    chicoduster

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    I own an Acroduster One and have done a few annuals on them. The fuselage is pretty simple (more like a midget mustang than a rag and tube plane). The biggest thing to look for is the front cabane mount where it connects at the bottom. To look you have to take the top fuselage piece off. This piece needs to be kept under tension or it breaks the mount. Mine had a problem with this I found at the second annual. You can't tell if it is broken by trying to jiggle it for the outside. This is apparently a problem with this plane. The wings are pretty standard wood build wings. The elevator attach fittings are not strap like the Pitts and are simple drilled aluminum hinges. They tend to wallow out over time so check out the play. The landing gear is very stiff and after any hard landing the mounting should be checked out thoroughly. Be very careful entering or exiting the cockpit as you don't want to step on the control mixer on the floor. As far as flying one , the pitch is really really sensitive. When you do your first landings move your hand down the stick to get rid of the PIO (pilot induced oscillations). This plane is FUN TO FLY and has been everything I wanted it to be. Enjoy
     
  5. Jun 17, 2018 at 3:59 PM #5

    n262ln

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    Bought my Acroduster Too last July. Many things not picked up on the prebuy. Aircraft finish work and frame welding were exemplary, however, not all that glitters is gold. Aircraft was built over a 30 year period and first flew in 2014. Aircraft had 52 hours TTAE when I picked it up. Here is a list of things not picked up on the prebuy.
    1) Hartzell prop had a recurring AD on the hub for yearly eddy current inspections as a result of cracks/catastrophic failures in a couple of Pitts S1's. Hub replacement was a must for me since I bought the plane for sportsman/intermediate aerobatics. Replacement set me back about $5000.
    2) Clearance between the spinner and nose cowling was roughly 1/32". Should be closer to 3/8". Had to shave 1/4" off the front of the nose cowl while adding an equivalent amount of fiberglass to the back of the nose cowl.
    3) Alternator mount bolts were not safety wired. One came off and the other was hanging by two threads when I landed. I shudder to think what would have happened if it completely let loose. Fortunately no damage.
    4) Landing gear bungees were circa 2008 and were frayed. Replacement required.
    5) Automotive steel tailpipes were substituted for mufflers. Their weight caused the engine exhaust stacks to break in half ($1600).
    6) Rear windscreen too small for me to wear my seat cushion parachute. Forehead about an inch above making cruise with a chute uncomfortable and inverted flight impossible (eyes above windscreen). Backpack and wedge chutes put me way too close to the stick. Had to redesign windscreen and have new one manufactured (~$1000).
    7) Throttle cable routed at too sharp an angle. After about 10 hours it started to stick such that you couldn't reliably get the throttle to completely close.
    8) Flop tube not flopping. Engine quits due to fuel starvation after about 30 seconds of inverted flight. Tank assembly (including flop tube) was purchased from Stolp in 1974. Apparently the flop tubes get stiff and need to be replaced every 3-5 years. Am currently looking for a replacement (sent Aircraft Spruce a request for just the flop tube as its part of the main inverted tank kit; awaiting response).
    9) Minor peeling of paint on empenage belly (a couple spots about two inches long). Associated paint cracks have not propagated.
    10) The aircraft has an enormous amount of drag. I get 120 mph at 75% power (200 hp IO-360 A1B6D). Not sure if this is normal (this is my first biplane) and am wondering if engine is developing rated power. Conditional comes up next month and will have that looked at then.

    The one thing I wish I'd done before purchase; fly the plane from the rear cockpit while wearing a parachute. The front cockpit wasn't as bad as the rear. Also rear cockpit is fine when sitting on the cushions.

    All that said, the airplane is an absolute blast to fly.
     
  6. Jun 17, 2018 at 5:05 PM #6

    cwilliamrose

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    On the speed issue -- check the rigging. It could be a mess and costing you 10MPH even if the airplane is flying near hands-off. It probably is not going to be the case but it is possible. It's cheaper than fixing the engine.......
     
  7. Jun 17, 2018 at 5:36 PM #7

    EAABipe40FF

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    Cockpit size and wearing a chute is a common issue. I had to make several adjustments to my Acroduster 2 including seat pan and different windshield.

    (Speed? Does indeed seem slow? My Starduster 2 with 200hp and fixed pitch 76X60 would do 140 IAS at 2400 rpm. I remember when I went to fetch it home it ran away from my buddy in a Piper Warrior, I had to really throttle back. It would keep up with a stock S1S if I pushed the throttle just a bit. I suspect like Bill does it may be flying crooked ? Angle of incidence on stab. can be a factor....Give Dave Baxter a PM as he is busy with his new build and may not see this.)

    Edit! I thought/misread SD2 and on 2nd reading see you have a AD2. Yes something is goofy. My AD2 does an honest 120 mph (double checked with GPS during phase 1) at 2500 rpm with a IO320-160hp.

    It would seem that if it's making honest rpm and MP the engine would be making the power? Maybe calibrate Tach?

    Jack
     
    Last edited: Jun 17, 2018 at 5:53 PM
  8. Jun 17, 2018 at 7:14 PM #8

    n262ln

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    Ok, so it's not normal to do 120 mph when running 24 squared. That would explain why my neighbor runs 18/2400 in his Eagle and I'm running 24 squared when we fly formation. I thought maybe the difference was the drag penalty paid for open cockpit. Are there flight checks I can do to verify proper rigging?
     
  9. Jun 17, 2018 at 7:36 PM #9

    cwilliamrose

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    In the Pitts world we use rigging boards to visually check and correct the rigging. I don't know about the Acroduster Too and its rigging requirements but others here do. Biplanes don't really lend themselves to flight checks to assess the rigging because it is possible for one rigging error to be canceled out by another rigging error on a different wing. The result can be that the four wing panels end up fighting each other which produces unnecessary drag.

    On a Pitts you can do ball centered stalls to see if a wing drops which would indicate the top wings' incidence is not matched left-to-right. If the airplane does not roll in the opposite direction than the wing dropped then the lower wings are probably twisted in the opposite direction to cancel the roll the top wing is producing. But you don't really know where the errors are and how much correction is required. The rigging boards tell you those things along with helping you get the top wing dihedral-free.

    In use they look like this;

    Rigging Boards in Place.JPG
     
    Last edited: Jun 17, 2018 at 8:46 PM
  10. Jun 17, 2018 at 7:47 PM #10

    EAABipe40FF

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    You can/should do the same on your Acroduster. All incidences are suppose to be zero including the stab(at least start there)

    I only used one board with a smart level on my airplane and it seems to be rigged pretty well although it does tend to drop one wing slightly in a ball centered stall. IMO and many others sighting across three boards is more accurate than a smart level and are the best method.

    Jack
     
  11. Jun 17, 2018 at 7:53 PM #11

    n262ln

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    Very interesting! When checking out in the aircraft the instructor, Rich Perkins, was surprised by which wing dropped during one of the uncoordinated turn stalls. I don't recall the exact configuration when he got surprised. Could very well be rigging. I'm not a builder (but am getting a lot of "fix it" experience) and rigging may well be above my pay grade. I'm going to have to seek help. Thanks so much for the info!
     
  12. Jun 17, 2018 at 9:54 PM #12

    Dave Baxter

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    Harry I will send some rigging information to your E-Mail address. But as Bill said the possibility of rigging issues may very well be a big part of the problem. The wings should as Jack said both at zero incidence, I suspect that you might have some positive incidence in one or both wings, that could be slowing it down. Cruise speed should be somewhere around 140 mph with a 200 hp lyc and constant speed prop. There are many other things that can effect a reasonable cruise speed. I presume that with a new overhauled prop it and the governor is set correctly, and have you flown with your friends Eagle since the new prop? All homebuilts are not the same. Here locally at one time comparing my airplane to other Starduster Toos, mine cruised at about 120 mph @ 2450, it has a 180hp lyc,and a fixed pitch propeller. My two friends had Starduster Toos, both with IO-360s, one with a C/S, and the other with a fixed pitch, the one with a fixed pitch prop would easily out run and routinely cruise around 130 mph the other one would barely make 110 mph, granted it had some engine issues since repaired and does better now, but it seems that the air did not want to go around, over the airplane or through engine cowling and baffles. I have found with the Starduster Too that installing a canopy can, but not always will, increase the speed from about 5 to 7 mph at the same rpm. A similar thing with open cockpit airplanes can be accomplished, by removing the front windscreen and covering the front cockpit as flush and as smooth as possible.

    Rigging seems for many to be an exercise in frustration, and for many after trying all sorts of remedy's usually end up with some sort of trim tab. Also many can get the airplane to fly straight, but it is still out of rig as Bill commented with one problem cancelling out another, or like a dog running down the road with his hind end off to one side, if this makes sense? Rigging should be a big part of building from the start, just like rigging the airplane prior to cover, unfortunately either is not usually the case. Dave

    P.S. Its kind of like the guy that flew his Piper Warrior from the Bahamas back to Florida with a concrete block still tied to one wing, and wondered why that wing was so heavy? But I suspect that you have no concrete block tied to your wing!
     
    Last edited: Jun 18, 2018 at 3:24 AM
  13. Jun 18, 2018 at 7:06 AM #13

    Jonas Larsson

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    Thanks all for input, much appriciated!

    BR Jonas
     

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