1
$\begingroup$

I was was thinking about buying a 80s rutan quickie q-1, it has a 18 hp motor. I want to get a ultralight but I like this one because it is fast. Can I get a motor that would be within the requirements? I don't know how I would be able to make this an ultralight. Iwas wondering if a Rutan 277 engine would work well in it and if this would be in the requirements

$\endgroup$
  • 1
    $\begingroup$ Possible duplicate of Is it possible to fly using a small engine? $\endgroup$ – fooot Oct 8 '18 at 15:38
  • 1
    $\begingroup$ Hi, welcome to aviation. I have tidied up/reworded your question and have hopefully kept the important parts of your question. Please have a look at the help center to find out more about asking/answering questions here. $\endgroup$ – Jamiec Oct 8 '18 at 15:55
  • $\begingroup$ If you don't get a good answer here, you might try quickheads.com. Because there are so many possible variations of kit aircraft, it's often useful to ask people who have actually built them. In general, builders/owners associations are a really good source for "could I do this?" questions. $\endgroup$ – Pondlife Oct 9 '18 at 2:35
  • 2
    $\begingroup$ You need to specify which country you're talking about, because the meaning of the word "ultralight" varies dramatically from country to country. In the United States, ultralights must weigh less than 254 pounds; in Brazil, they can weigh 1,500 pounds. $\endgroup$ – Terran Swett Oct 9 '18 at 13:04
  • $\begingroup$ I edited your title to more closely match your actual question -- if that isn't what you're trying to do, feel free to roll it back (once it's passed peer review). $\endgroup$ – Zeiss Ikon Oct 9 '18 at 14:33
5
$\begingroup$

I doubt the Quickie would fly well enough at very slow speeds to meet the rest of the Part 103 requirements -- specifically, the limit on maximum level flight speed. Limiting fuel capacity is easy, and the 18 HP original engine worked well enough on the Q1 -- but it was a lot faster than 55 kt (close to double, as I recall). From comments (thanks, Gerry) I understand the Q1 has a stall speed of 42 kt -- fairly reasonable for a light aircraft, but well above Part 103 maximum of 24 kt.

You might be able to slow down enough by installing a flatter-pitch propeller, but that would have other effects (overspeeding the engine, for instance) that would need to be addressed, and then you'd be trying to fly with almost no speed range -- 42 to 55 kts isn't, IMO, a safe performance envelope (and yes, the Q1 would still go faster than 55 kt in a dive, but the level flight and climb performance are where the safety issues lie in this case).

$\endgroup$
  • $\begingroup$ It won't meet the 24 kt maximum stall speed requirement of Part 103.1(e)(4) even if you could find a way to make it slow enough without destroying the flying qualities. The published stall speed of the Q1 is about 42 kts. Having helped a friend build one, I can say this is not what you want if you're looking for an ultralight. It could however qualify as an LSA. $\endgroup$ – Gerry Oct 8 '18 at 16:32
  • $\begingroup$ does anyone know of a ultralight thats afordable, that is a closed cockpit. Because all these ultralights im seeing are kinda ugly, lol $\endgroup$ – Blackhawk 19 Oct 8 '18 at 16:55
  • 1
    $\begingroup$ @Blackhawk19 There are several -- but this forum isn't set up to answer that question, even if you ask it as a proper question (shopping questions are generally OT on Stack Exchange sites). Might want to ask in chat or on a discussion forum. $\endgroup$ – Zeiss Ikon Oct 8 '18 at 16:59
  • $\begingroup$ @Blackhawk 19: Beauty is in the eye of the beholder, of course, but most of what you seem to think is ugly in ultralights is a consequence of needing low weight, top speed, and stall speed to qualify as an ultralight in the first place. $\endgroup$ – jamesqf Oct 8 '18 at 17:08
  • $\begingroup$ @Blackhawk19 and not to mention that there are a number of ultralight legal aircraft that I find quite graceful and pleasing to the eye. Look for the ones with composite structure and skin -- like the Carbon Dragon sailplane. $\endgroup$ – Zeiss Ikon Oct 8 '18 at 17:30
0
$\begingroup$

Speed is not just about the engine. The reason the Q1 is so fast on an 18HP engine was that it had high wing loading, to put it a simple way it has to fly faster for the wings to produce enough lift. Its stall speed is about 41 knots, which is a characteristic of the wing shape and area, if you put a smaller engine on it you won't change the characteristics of the wing.

$\endgroup$
0
$\begingroup$

If it had a lighter engine, the wing loading would be slightly smaller. If it could be rewinged (longer chord and more camber?), then it might work. You could get enough lift at a slower speed. A bigger wing would weigh more, but perhaps that would be offset by the lighter engine. Of course, the CG would change and the wings would need to account for the shift in cg.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.