Firebolt roll issue

Discussion in 'Skybolt Miscellaneous' started by gmatejcek, Sep 4, 2018.

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  1. Sep 4, 2018 #1

    gmatejcek

    gmatejcek

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    Hi All- I'm looking for some feedback from folks with Firebolt experience. I've recently partnered in one that has surprisingly heavy aileron forces and not-exactly-blinding roll rate. There aren't any spades mounted, and a friend who is an aero engineer, homebuilder, and acro competitor is hesitant to just add them. Does the collective have any insights into or experience with this situation? IE, do other Firebolts have heavy ailerons? Has anyone added the spades, and do they like the results?

    Thanks in advance for your input!
     
  2. Sep 4, 2018 #2

    cwilliamrose

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    If you could post some detail photos of the ailerons that might help. Things like the aileron LE, the coves, the aileron TE and the overall size of the ailerons, etc.
     
  3. Sep 4, 2018 #3

    cgzro

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    Your friend is correctly cautious about adding them wothout a proper test program. It can be very dangerous.
     
  4. Sep 4, 2018 #4

    gmatejcek

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    Thanks guys- I'm on the road so unable to get pix, but to my knowledge they are to plans. Nothing obvious is amiss, all is square, no rubs in the control system, and the ailerons are thicker than the wing at the cove. Once back in town I can see about uploading pix. What perspective would be most useful / what are we looking for exactly?
     
  5. Sep 4, 2018 #5

    cwilliamrose

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    I'd be interested in seeing the LE radius, the gap to the cove and the cove's profile. On the TE the geometry and thickness are of interest. I'd also like to understand the deflections up and down and the amount of stick travel it takes to get to full travel. Maybe others would have something to add to the list. That there are no rubs or binding is good to know. What type of bearings does the aileron control use (hinges, idlers, bellcranks)? Is there any noticeable friction in the system (on the ground)? Is the torque tube free to rotate?
     
  6. Sep 14, 2018 #6

    gmatejcek

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    There are no issues static. Stick forces and travel are unremarkable. The plane flies fine... if you like cessnas. Getting an almost- decathlon roll rate takes a LOT of force. And, no, I’ve rolled a number of types and I’m not anorexic. Pix shortly
     
  7. Sep 14, 2018 #7

    Dennis Flamini

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    i think you have to notify the FAA and do 5 hrs phase 1 testing with logbook entry.
    Check your operating limitations.
     
  8. Sep 14, 2018 #8

    cashflyer

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    Spades do nothing to increase roll rate; they only lighten the stick forces.
    If your Firebolt has properly rigged wings and properly built ailerons (4 of them) then there's not much you can do.

    I believe the ailerons on the Firebolt are the same as the Skybolt, except having three hinges instead of two. I had plans for both, but they were sold last year so I cannot reference them.
     
  9. Sep 14, 2018 #9

    gmatejcek

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    It turns out the gap seals are missing. I recently saw pix of the pretty green firebolt t B866C614-353D-45DD-A1A7-BF1CFB42A3EB.jpeg 9FC20E50-053C-4279-A710-BDF7E7015AF3.jpeg 44AAC516-A6ED-4D2A-8242-560708FDAFFB.jpeg 1D0DFF9F-56D5-4E30-AC75-A717E48C97FC.jpeg 34E6B41F-475D-46BB-B55C-C1930561C788.jpeg hat was at osh this year, and it seemed the same as ours. Unfortunately, it had departed before I could get over to it and take a gander for myself. I was hoping there were firebolt owners on this forum that could offer comparative data, as this level of performance kinda defeats the purpose of owning the plane in the first place. A couple skybolt guys were amazed at how heavy these ailerons are.
     
  10. Sep 14, 2018 #10

    cwilliamrose

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    Aahh! Symmetrical ailerons, no wonder they're heavy!! But they should provide good roll authority if the builder increased the chord of the ailerons as much as possible. That's one of the advantages of that design over the 'normal' Frise ailerons. They may be rigged with less deflection than they should be, that's something to check.

    You're going to need spades just as the S-2B has spades to reduce the stick force on their symmetrical ailerons. Making covers to close the gaps around the hinges will help the roll rate some and will be worth doing once you get the stick forces in a better place.
     
    Last edited: Sep 15, 2018
  11. Sep 14, 2018 #11

    gmatejcek

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    Cool, and thanks. I’ll get with our brain trust and see if we can’t get the process moving forward. I’ll send updates as they are available.
     
  12. Sep 15, 2018 #12

    Laxinator

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  13. Sep 16, 2018 #13

    gmatejcek

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  14. Sep 16, 2018 #14

    Aerocruz

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    When I purchased my Firebolt, 4GW, back in 2011 I assumed I would want to purchase spades. I believe it was Raven Aircraft who I contacted who asked me to provide them with some measurements to custom manufacture the spades. After a few aerobatic routines, I found the ailerons to be light enough that I chose not to purchase and install the spades. I certainly would not consider the deflection pressure to be heavy and is light enough for enjoyable weekend aerobatics. I have not flown a pure Skybolt design for comparison. My pressure comparisons come from flying another pure Firebolt design, some time in a Decathlon and a little time in a Pitts S2A and S2C. The retired Air Force General that I purchased the bird from had the same initial intentions just after purchasing 4GW from the builder, but wound up coming to the same conclusion that the spades were not necessary. I will be happy to take some pictures of the ailerons next time out at the airport if you would like.
     
  15. Sep 16, 2018 #15

    cwilliamrose

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    I'm assuming the Firebolt (as designed) has Frise ailerons like the Skybolt. Those ailerons are aerodynamically balanced, the symmetrical ailerons are not and require external aero balancing to lower the stick forces. I have not flown an S-2B without spades but I'm told it is pretty heavy on the ailerons without them. I did fly an S-1 derivative with symmetrical ailerons and no spades and it was firm at cruise speed. I'm sure it would have been uncomfortably heavy at high speed.

    I'd like to see some photos of your ailerons Aerocruz to compare the the other airplane.
     
    Last edited: Sep 16, 2018
  16. Sep 16, 2018 #16

    gmatejcek

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    I would appreciate that. Do you have the aluminum gap seals extending back from the cove T.E.'s?
     
  17. Sep 17, 2018 #17

    Aerocruz

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    4GW does not have the gap seals that I saw on air show performer Randy Harris’ bird. Is a tight fit and very well balanced. Will try to get out to the airport some time this week to take some pictures. BTW, I like the look of your Firebolt. What’s the history on your bird?
     
  18. Sep 17, 2018 #18

    gmatejcek

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    As I understand it, this airframe was started by McKenzie, then sold with the bulk of the structural work done. The second owner donated the completed airframe to a charity who then resold it. The last previous owner had a landing accident, resulting in a major rebuild by the owner and some professional help. It then became a hangar queen, ultimately ending up in our hands.
     

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