Kitspace

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About Kitspace

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    Sr. Spacecraft Engineer

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  1. I trust you are well? Any news?
  2. Interesting. I guess real life planes also have limitations on speeds for operations of such mechanisms... Sort of like the speed limit with the gear down is higher than while it is in motion quite often... Can not wait for the 1.4 release too!
  3. In the first two documents, each page with the velocity contours contains the thrust value, near the top of the page. And the reference at the page bottom shows for which engine types that page is valid. And I shall take a look at the idle thrust levels in the new version released, should be better now, I think
  4. Sorry, I did not make myself clear enough, I mean when you do that, do your wings not become wobbly and break off, while they are in motion?
  5. Sorry, not sure, what you mean by that? All three links contain numbers on thrust at different throttle settings for the different engine types
  6. I was just reading the thread and I am interested, if you have to keep the lock engaged, how do you change the wing position in flight, without breaking them?
  7. Are the links on the previous page the kind of data you are looking for?
  8. Kitspace

    AJE Extended Configs

    All turbojets have the thrust falloff to an extent. Now I am starting to think it is something to do with the cone intake I am testing them with. Could this be the case? But all the turbofans and turboprops with built in intakes also have the falloff that I think is too rapid to be realistic. CF6 is stock and the CFM56 from Airplane plus
  9. More on JT8 https://www.boeing-727.com/Data/engine/engdata.html
  10. Kitspace

    AJE Extended Configs

    I found a couple of links which seem to give an idea of the sort of thrust turbofans have at idle. http://www.boeing.com/assets/pdf/commercial/airports/acaps/767sec6.pdf http://www.boeing.com/assets/pdf/commercial/airports/acaps/777rsec6.pdf And as an example of a smaller low bypass turbofan. 16000 pounds of normal takeoff thrust and 1040 pounds of idle thrust is quoted for a JT8D-17. Also as I understand the engines with a variable geometry nozzle should generally have slightly lower values than those with a simple fixed one as the nozzle aperture opens wide when idling and reduces the exhaust velocity.
  11. The docs in the following links can give an idea of what the idle thrust of a high bypass turbofan engine should be compared to its rated takeoff thrust. http://www.boeing.com/assets/pdf/commercial/airports/acaps/767sec6.pdf http://www.boeing.com/assets/pdf/commercial/airports/acaps/777rsec6.pdf For the smaller low bypass turbofans it usually seems to be in the region of 6-7%. For example people quote takeoff thrust of 16000 pounds and idle thrust of 1040 in standard conditions for a JT8D-17. For pure turbojets I do not have concrete data but it seems to be slightly higher again at around 8-10%. I hope this proves useful and will try to find more data for different examples and such. Also the general rule of thumb from the point of view of a pilot is that the aircraft can taxi without slowing down at all at ground idle thrust but quite a bit more is required to get it rolling at first. So I guess a reasonably made kerbal aircraft with a realistic thrust to weight ratio should do the same? How hot is Kerbal Space Center? I have always thought Kerbal Space Program does not simulate any weather or non standard conditions... That might be the explanation then. And with regards to speed I was going back and forth down the runway to test that. So altitude should not be a factor here.
  12. Kitspace

    AJE Extended Configs

    I have no problems with turbofans having high idle thrust, but still it seems exaggerated to me. Sometimes planes are accelerating like crazy when taxiing with closed throttles because of this high idle thrust, yet hardly reach 70-80m/s, just because thrust halves at that speed for some reason. Also, as an example, idle thrust of a CFM56 is higher than that of a CF6, despite the latter engine being much bigger, with more than double the rated thrust, which seems strange. Is it really supposed to be that way? In what situations are turbofans supposed to give the rated thrust? I thought that should be just static at sea level?
  13. Is it just me or do some of the engines, mostly turbofans, have really high idle thrust levels, yet do not develop their rated thrust at full throttle? Also the thrust seems to fall off extremely fast with speed... Even with pure turbojet engines... Why is that happening?
  14. Kitspace

    AJE Extended Configs

    Is it just me or do some of the engines, mostly turbofans, have really high idle thrust levels, yet do not develop their rated thrust at full throttle? Also the thrust seems to fall off extremely fast with speed... Even with pure turbojet engines... Why is that happening?
  15. Kitspace

    Official FAR Craft Repository

    Thank you for helping me! As I understand it the main change regarding the pitch stability comes from moving the stabilizer higher and further aft. Doing the same thing on my version gives an interesting effect. The craft becomes both more stable and more controllable simultaneously. Can you please post a picture of your static stability page at the landing conditions with full pitch up input? What angle of attack is it capable of? To me taking off and landing at 100 meters per second looks like a lot actually. Could it be that the difficulties you are experiencing with landing are due to the high speed? In terms of the actual lifting force the thing can lift off the runway at 70-80 ms. The only difficulty I found is making it pitch up high enough for that. It can be done with stabilizer incidence angle but then it requires a lot of forward pressure on the stick in order to prevent pitching up in flight. A movable stabilizer would probably solve the problem but it seems to be quite difficult to make a kerbal version of one. Anyways an adjustable stabilizer is used to allow for a bigger range of center of gravity as far as I know. And in this plane the center of gravity does not move a lot if at all. By the way cheers for the flag.