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Q2 Stall Speed

8 years 3 months ago #1521 by scheevel
Replied by scheevel on topic Q2 Stall Speed
I would really like to help you, but you are rambling in search of the answer you want, which is how to make the Q-2 into a 42 knot landing bird.

First of all, that entry in the log for your Q-2 by the "test pilot" is wrong. Probably was put there to get you to buy the plane. Others claiming to land that slow may be talking about the single seat Q-1, which is much much lighter (around 200 pounds empty weight) and has 54 square feet of wing area. By your own admission, you are not yet a pilot, so you have no practical basis to judge the accuracy of flight reports and no true sense of practical aircraft performance.

As far as making the Q-2 into a microlight, it is not possible. It may be possible with single seat Q-1.

Unfortunately, you have substituted your instincts (which are misguided) in place of actual knowledge on aerodynamics. If you really want to do some of this stuff yourself, then you need to educate yourself with the actual science. Get a text on basic aircraft design. You seem to think that the fuselage is an efficient lifting device, not so. The F-15 example you quote is probably drawn from the case of the Israeli test pilot who ripped the right wing off his F-15 in a training collision and then landed without it. He needed to hold nearly full thrust, full left aileron on the remaining wing (courtesy of computer/fly by wire and hydraulics) then land at 250 knots. This is not efficient.

Please educate yourself starting with some basic texts, then you will realize where your misconceptions are. Once you do this, I may be able to help you further.

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8 years 3 months ago - 8 years 3 months ago #1523 by AlanThomas
Replied by AlanThomas on topic Q2 Stall Speed
The answer to the question as to whether or not Q2 can achieve flight at 45 kn is yes but in order to qualify the yes we first need to understand the aerodynamics in order to configure the craft for that speed. We must remember its namesake which has "quickie" and not "slowly" because as we all know there are inherent difficulties in achieving aerodynamics for low powered high-speed craft that can also fly slow.

be verified figures of my plane include a 39 kn levitation speed and a breakthrough of the ground effect at 42 kn. pre-bobbing speed can be set up to only 50 kn. These figures are not inconsistent with the early demonstration the World War II flying Tigers targeting photographer later demonstrated to the Chinese when they purchased I think about 10 Q2 in the early 80s I think in Shanghai. Although his own Q2 was a turbo Revmaster that managed over 20,000 feet I don't think his head is in the clouds in regards to the full spectrum of the darling little aircraft.

I take the view that what was achieved in the 1980s can now be exceeded quite easily with current technology such as though the entire Q2 out of lighter materials combined with sophisticated flap arrangements will more than easily reach the objective of registering these craft as microlights/ultralights in countries like New Zealand that let you go whatever speed you dam well please. But a wide go that far if we find that can already do with just a few tweaks/add-ons to clip just a few more knots off the pre-bobbing speed.

The basic aerodynamic principle is the same wing will not achieve the both tasks easily if at all.a cursory examination of the aerodynamics indicate that there will need to be significant extensions flaps and suchlike to the wings if not even having a pop out third wing deployed when wishing to achieve low speed.

Of course significant modifications to the wings does advanced the original design well beyond its original cheap and cheerful objective. However it still does not need to be expensive. The benefits would be rapidly increased population of Q2 craft as they would then be able to be re-rated as microlights or ultralights depending on which country you are and whether or not that country has a top speed limit.

After all it is only engineering!
I for one think we should engineer the hell out of this wonderful little aircraft in a manner consistent with what the Chinese are up to which includes an electric motor which may be as high as 50 kW which allows short bursts such as the takeoff with powder goes way off the chart.

In the meantime before we get into too much altitude we should get back to basics and address the questions I have already posed such as the limits of the existing design including the numbers for all of the lifting services including the fuselage itself. Once we know what the target is we can then take proper aim to achieve it.
Last edit: 8 years 3 months ago by AlanThomas. Reason: add on

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8 years 3 months ago #1524 by AlanThomas
Replied by AlanThomas on topic Q2 Stall Speed
I appreciate the members input that utilises my broad shoulders and thick skin. However I'm interested in the avionics of the question such as the extent the Q2 contributes towards the overall lift which therefore must be factored into the finely tuned lowest possible speed arrangement prior to exploring the feasibility of targeting Q2s as being microlight and/or ultralight craft.

I think we can recognise that the wings of the Q1 and Q2 are much the same yet the lift characteristics are different which is not just applicable to the overall weight as the arithmetic doesn't go that far indicating the importance of the lifting characteristics of the fuselage. Let's not forget that Burt Rutan is one of the foremost experts when it comes to the design of lifting bodies so we need to look and understand what is thinking and rationale was. I think my enquiry was not unreasonable.

I'm sure we are all aware of the lower performance of the Dragon fuselage lifting characteristics when the objective of that craft was to achieve lower speed combined with the various other elements that did not achieve the objectives that were hoped for. Having said that the Dragon for sale in New Zealand at the moment has a video demonstrating that it does not enter into the bobbing hysteresis until below 60 mph which is quite a lot lower than other figures quoted.

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