i am a trained welder fabricator (and was previously coded to ASME9) which you would think would help but obviously i would need to be qualified to work on anything that is going to fly.

im now at a point where im considering joining the army as an aircraft technician which will give me the training and qualifications i need when i leave but is quite a comitment.

does anyone have any advice for me on how to get into aircraft restoration/working on planes without joining the army?

any advice would be greatly apreciated.

cheers,

josh.

Statistics: Posted by Higgins420 — Sun Feb 28, 2021 8:10 pm

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Thanks

Statistics: Posted by IWF — Fri Feb 26, 2021 6:28 pm

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Good after-sales from Ufly also, very responsive, nothing too much trouble.

Rob P

Statistics: Posted by Rob P — Fri Feb 26, 2021 6:07 pm

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Statistics: Posted by cjrpaterson — Fri Feb 26, 2021 7:48 am

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Anyone any experience of anything like uflymike or their competitors?

Statistics: Posted by IWF — Thu Feb 25, 2021 7:48 pm

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Statistics: Posted by T67M — Tue Feb 16, 2021 10:47 pm

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Thank you.

Statistics: Posted by flyingearly — Tue Feb 16, 2021 4:21 pm

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It seems to me that using best glide speed as an approximation for Vy is a pretty hit and miss approach:

Code:

` AA5B Vy 90Kt IAS Best glide 72Kt IAS`

And for comparison between the AA5B and AA5A:

Code:

` AA5A Vy 79Kt IAS Best glide 72Kt IAS`

The Cheetah and Tiger airframes are virtually identical, but the Tiger (AA5B) has a more powerful engine (and a beefier spar).

So it's not surprising that their best glides are the same, but the Vy values significantly different.

Statistics: Posted by TopCat — Fri Feb 12, 2021 6:45 pm

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Code:

` C152 Vy 67Kt IAS Best glide 60Kt IAS`

C172 Vy 76Kt IAS Best glide 65Kt IAS

AA5B Vy 90Kt IAS Best glide 72Kt IAS

TB10 Vy 78Kt IAS Best glide 86Kt IAS

WarriorII Vy 79Kt IAS Best glide 73Kt IAS

Dakota Vy 85Kt IAS Best glide 85Kt IAS

Statistics: Posted by GrahamB — Fri Feb 12, 2021 8:40 am

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Rob P

Statistics: Posted by Rob P — Fri Feb 12, 2021 7:46 am

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We use 85 kt.

Rob P

Sorry Rob. Got distracted and then haven’t had time to visit since.

It’s kinda been argued already, but generally Vy is pretty close to best glide for most airframes and most mere mortals.

There is a difference, there are exceptions, if you’re after an exact number then an aeronautical engineer is probably better. But in the real world and in practice you won’t be too far out.

Interesting discussion though

Statistics: Posted by AndyR — Thu Feb 11, 2021 10:58 pm

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G

Statistics: Posted by Genghis the Engineer — Thu Feb 11, 2021 12:41 pm

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Flyin'Dutch' wrote:Genghis the Engineer wrote:Antonio Filipone's book "Flight Performance of Fixed and Rotary Wing Aircraft" which is considerably more thorough than either shows even more maths, and a condition for maximum angle of climb for a piston-prop aeroplane with six terms in the equation.

Ignoring for a minute that this would be max angle rather than Vy - out of interest what are those 6 terms?

Air density, engine power, weight, wing area, propulsive efficiency, engine power. and the Oswald span efficiency variable. (plus speed and angle)

G

Engine power twice - must only apply to twins then?

Statistics: Posted by lobstaboy — Thu Feb 11, 2021 12:36 pm

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Genghis the Engineer wrote:Antonio Filipone's book "Flight Performance of Fixed and Rotary Wing Aircraft" which is considerably more thorough than either shows even more maths, and a condition for maximum angle of climb for a piston-prop aeroplane with six terms in the equation.

Ignoring for a minute that this would be max angle rather than Vy - out of interest what are those 6 terms?

Air density, engine power, weight, wing area, propulsive efficiency, engine power. and the Oswald span efficiency variable. (plus speed and angle)

G

Statistics: Posted by Genghis the Engineer — Thu Feb 11, 2021 9:52 am

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Antonio Filipone's book "Flight Performance of Fixed and Rotary Wing Aircraft" which is considerably more thorough than either shows even more maths, and a condition for maximum angle of climb for a piston-prop aeroplane with six terms in the equation.

Ignoring for a minute that this would be max angle rather than Vy - out of interest what are those 6 terms?

Statistics: Posted by Flyin'Dutch' — Wed Feb 10, 2021 9:11 pm

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Hale's "Aircraft Performance, selection and design", my favourite aircraft performance and sizing book from when I was an undergraduate, shows a bunch of maths and how to work it out, showing it is a bitch to work out.

Wikipedia says it's at the point of max excess thrust.

Antonio Filipone's book "Flight Performance of Fixed and Rotary Wing Aircraft" which is considerably more thorough than either shows even more maths, and a condition for maximum angle of climb for a piston-prop aeroplane with six terms in the equation.

Then I stopped and sketched it out.

Yeah, you chaps are right, I'm over-complicating it.

G

Statistics: Posted by Genghis the Engineer — Wed Feb 10, 2021 4:07 pm

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Genghis the Engineer wrote:GrahamB wrote:Of course, it’s defined as the speed that gives best angle of climb, but that’s where excess thrust is at its greatest.

The point where excess thrust is at its greatest is actually the point of greatest acceleration in level flight - a condition of basically no interest to anybody but fighter pilots.

G

A nice coincidence then.

It's not a coincidence. It's physics - it has to be the same.

Statistics: Posted by lobstaboy — Wed Feb 10, 2021 3:22 pm

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GrahamB wrote:Genghis the Engineer wrote:Your definition of Vx however is wrong - Vx is all about climb angle, not thrust

Of course, it’s defined as the speed that gives best angle of climb, but that’s where excess thrust is at its greatest.

The point where excess thrust is at its greatest is actually the point of greatest acceleration in level flight - a condition of basically no interest to anybody but fighter pilots.

G

A nice coincidence then.

Statistics: Posted by GrahamB — Wed Feb 10, 2021 11:45 am

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Genghis the Engineer wrote:Your definition of Vx however is wrong - Vx is all about climb angle, not thrust

Of course, it’s defined as the speed that gives best angle of climb, but that’s where excess thrust is at its greatest.

The point where excess thrust is at its greatest is actually the point of greatest acceleration in level flight - a condition of basically no interest to anybody but fighter pilots.

G

Statistics: Posted by Genghis the Engineer — Wed Feb 10, 2021 11:40 am

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Your definition of Vx however is wrong - Vx is all about climb angle, not thrust

Of course, it’s defined as the speed that gives best angle of climb, but that’s where excess thrust is at its greatest.

Statistics: Posted by GrahamB — Wed Feb 10, 2021 11:33 am

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But yes, excess power is to be fair, a better term.

Your definition of Vx however is wrong - Vx is all about climb angle, not thrust.

G

Statistics: Posted by Genghis the Engineer — Wed Feb 10, 2021 11:20 am

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Vy will be the speed, roughly speaking, where you have the greatest excess thrust that you can turn into climb rate.

Sorry G but that is wrong.

Vy is the speed where you have the greatest excess

Statistics: Posted by GrahamB — Wed Feb 10, 2021 11:02 am

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https://aviation.stackexchange.com/questions/73997/how-can-best-glide-speed-be-lower-than-best-rate-of-climb-speed

This shift can be high enough that Vy ends up higher than Vg.

The Vy is always higher than the speed for the best climb angle, because these two speeds are found on the same (max power) power curve. For the same reason best glide speed will be always higher than speed for minimum sink. But speeds for best rate of climb and for the least sink does not need to be the same because of effects of real propeller."

Statistics: Posted by Paul_Sengupta — Wed Feb 10, 2021 10:17 am

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TopCat wrote:But that doesn't change the fact that max(L/D) doesn't happen at Vy, except by accident.

Physics rarely has anything to do with 'by accident'

Well of course, by 'by accident' I was neither saying nor implying that physics is non-deterministic. "By accident" in this context means 'as a deterministic consequence of at least partially different causes'.

I am sure that Vy is not exactly the same as best glide as a power off (of idling engine) airframe is a different airframe than that with a pulling engine, but it will be close.

No one is disputing that it will be close. What is neither obvious, nor shown in anything I've read on the subject, is a relationship between Vy (the airspeed for max(power available - power required)), and the airspeed where L/D happens to be a maximum in the glide, which of course has nothing to do with the engine.

Flyin'Dutch' wrote:

Best glide = Vy if Best glide is furthest glide.

... but what is clear, is that this is not so.

Any more detail than this is above my pay grade, so hopefully someone with real knowledge of aeronautics will be along. It would be nice to know in detail why the numbers are close.

Statistics: Posted by TopCat — Wed Feb 10, 2021 8:47 am

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But that doesn't change the fact that max(L/D) doesn't happen at Vy, except by accident.

Physics rarely has anything to do with 'by accident'

I am sure that Vy is not exactly the same as best glide as a power off (of idling engine) airframe is a different airframe than that with a pulling engine, but it will be close.

Statistics: Posted by Flyin'Dutch' — Tue Feb 09, 2021 5:57 pm

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TopCat wrote:Flyin'Dutch' wrote:Best glide = Vy if Best glide is furthest glide.

No. It will be close to it, probably, but they're not the same.

Given that Vy is the speed where the excess of power available vs power required is a maximum, it is dependent on power.

Best glide is the speed at which L/D is maximum, which isn't.

__

Edit: added 'is a maximum' above. Now a whole sentence, sorry!

TC so you think that Vy is dependent on power?

Well it's a good question.

I suppose if you took the engine out, replaced it with one of a different power but the same weight, and the power available curve was exactly the same shape as the one before (just higher than, and parallel to it at all points), it wouldn't be, as the airspeed at max(available - required) would be in the same place as before.

So I guess I should have said that it's dependent on that power excess, not just the power on its own.

But that doesn't change the fact that max(L/D) doesn't happen at Vy, except by accident.

Statistics: Posted by TopCat — Tue Feb 09, 2021 5:04 pm

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Flyin'Dutch' wrote:Best glide = Vy if Best glide is furthest glide.

No. It will be close to it, probably, but they're not the same.

Given that Vy is the speed where the excess of power available vs power required is a maximum, it is dependent on power.

Best glide is the speed at which L/D is maximum, which isn't.

__

Edit: added 'is a maximum' above. Now a whole sentence, sorry!

TC so you think that Vy is dependent on power?

Statistics: Posted by Flyin'Dutch' — Tue Feb 09, 2021 3:29 pm

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