CAtegories and Manoeuvres
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CAtegories and Manoeuvres
Hi!
I was wondering what kind of manoeuvres are certified on the PA38 Tomahawk.
Also why on the Utility category the loop, spin and barrel roll are permitted but the whip stall is not?
Regards,
R.
I was wondering what kind of manoeuvres are certified on the PA38 Tomahawk.
Also why on the Utility category the loop, spin and barrel roll are permitted but the whip stall is not?
Regards,
R.
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Probably because the whip stall will overstress something in the aeroplane.
Main Entry: whip stall
: a stall during a vertical climb in which the nose of the airplane whips violently forward and then downward
: a stall during a vertical climb in which the nose of the airplane whips violently forward and then downward
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Don't know about loops and rolls, but I'm pretty sure the Tomahawk *is* allowed to be spun - it's their spinning characteristics that earned the 'traumahawk' moniker.
Your placards may be due to operator regs, or possibly AD's that haven't been applied, though I'd expect those would be up to date.
Ric00: Short answer is read the POH!
Your placards may be due to operator regs, or possibly AD's that haven't been applied, though I'd expect those would be up to date.
Ric00: Short answer is read the POH!
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PA38 is allowed to spin in the UK under certain conditions.
It must have a 5 point harness fitted and the C of G must be between certain limts and about 6 mods have to be have done to the tail.
A loop and barrel roll is not permitted in the UK although I am sure someone has done them.
The POH is your bible
It must have a 5 point harness fitted and the C of G must be between certain limts and about 6 mods have to be have done to the tail.
A loop and barrel roll is not permitted in the UK although I am sure someone has done them.
The POH is your bible
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You won't die doing either of those manoeuvres in a PA38.
The loop will shag the engine because its not built for it but the aircraft won't drop out of the sky or the tail fall off. Students recovering from spiral dives when the speed gets up, pull way more G than a loop. Its a function of the oil system on the engine amongst other things
Barrel roll in the right hands (not mine I may add) will not do anything at all to the aircraft. Allegedly Concorde did one may years ago.
Its a matter of the certification. As I said before I am sure these manoeuvres have been done before but I certainly wouldn't recommend it and I will never be in a PA38 when it does them.
The loop will shag the engine because its not built for it but the aircraft won't drop out of the sky or the tail fall off. Students recovering from spiral dives when the speed gets up, pull way more G than a loop. Its a function of the oil system on the engine amongst other things
Barrel roll in the right hands (not mine I may add) will not do anything at all to the aircraft. Allegedly Concorde did one may years ago.
Its a matter of the certification. As I said before I am sure these manoeuvres have been done before but I certainly wouldn't recommend it and I will never be in a PA38 when it does them.
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Good point well presented.
Although along the barrel roll side of things it is usually do as I say not as I do. The Concorde case being the point in proof.
The old 707 did a barrel roll as well much to Boeings upset.
Although along the barrel roll side of things it is usually do as I say not as I do. The Concorde case being the point in proof.
The old 707 did a barrel roll as well much to Boeings upset.
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The loop will shag the engine because its not built for it [...] Its a function of the oil system on the engine amongst other things
You won't die doing either of those manoeuvres properly in a PA38.
The problem of course is when you fail to do them properly. In both manoeuvres you might end up nose-down, approaching Vne and needing way too much up elevator to recover from the dive, overstressing the airframe, engine mount, you name it. If you roll at the same time those forces are increased at the wing roots, leading to bent wings or worse.
Aerobatic aircraft have sufficient strength in reserve to survive most wrongly executed manoeuvres, and that's why you should be practicing aeros in an aircraft certified for them. Rumour has it that the Concorde, the 707 and a few more airliners have been looped and/or barrel-rolled. But this was not done by novice aerobatics pilots.
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The thing with the old 707 story was that Tex Johnston managed to keep a constant 1g throughout the manoeuvre. He knew what he was doing, which is why he was Boeing's chief test pilot.
In theory it's entirely possible with any aeroplane, as long as you keep at a constant 1g. Of course, it's not exactly legal with most aeroplanes, and for good reason.
There was an accident a while back in America when a pilot with no aerobatic experience attempted to barrel roll a Beech Baron, a la Tex in the 707 prototype. The wings fell off and what was left of the Baron sans aerofoils fell to Earth rather quickly, along with its unfortunate pilot. Oops
Smithy
In theory it's entirely possible with any aeroplane, as long as you keep at a constant 1g. Of course, it's not exactly legal with most aeroplanes, and for good reason.
There was an accident a while back in America when a pilot with no aerobatic experience attempted to barrel roll a Beech Baron, a la Tex in the 707 prototype. The wings fell off and what was left of the Baron sans aerofoils fell to Earth rather quickly, along with its unfortunate pilot. Oops
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Could you expand on this a little? Is the oil pump not capable of pumping the oil 20 cm or so into 4G or am I reading this incorrectly?
Most none aero engines have wet sumps and the oil is pumped directly from there. Aerobatic engines have scavenger pumps in the sump which then take it to a tank which means when you play silly sods a supply of oil is maintained to the bits that need it. And even if that's bollocks its as good a reason as any for me not to do aero's in a PA38.
And as for the rest of your post you are spot on in my view.
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Ok, I did wonder about that, but wasn't going to open the door.. as backpacker has: Hypothetically it should be perfectly possible to complete a loop with mild and entirely positive G, within the certified G limits of the aeroplane. It won't be round, but...
Barrel roll is probably one of the nastier ones if done as a proper barrel roll (rolling G), let's not start the 'is a one G manouver' misconception. What a lot of people call a barrel roll is really an aileron roll and not half as bad..
As has been said, there's no reason the wings would fall off, but there's very little margin for error, and very good reason to do so.
The aforementioned whip stall sounds a lot like a tailslide, or at least something that could very easily turn into a tailslide - in which case the biggest likelyhood of damage through mishandling is to the tailfeathers. As anecdotally they seem to flap around a bit on the '38 (never flown one), that would seem a good reason to avoid.
Quite simply there are plenty of perfectly good aerobatic aircraft out there designed to take the stresses, and also to leave you a reasonable chance of getting away with minor stuffups. Why risk it?
Barrel roll is probably one of the nastier ones if done as a proper barrel roll (rolling G), let's not start the 'is a one G manouver' misconception. What a lot of people call a barrel roll is really an aileron roll and not half as bad..
As has been said, there's no reason the wings would fall off, but there's very little margin for error, and very good reason to do so.
The aforementioned whip stall sounds a lot like a tailslide, or at least something that could very easily turn into a tailslide - in which case the biggest likelyhood of damage through mishandling is to the tailfeathers. As anecdotally they seem to flap around a bit on the '38 (never flown one), that would seem a good reason to avoid.
Quite simply there are plenty of perfectly good aerobatic aircraft out there designed to take the stresses, and also to leave you a reasonable chance of getting away with minor stuffups. Why risk it?
If we disregard the legalities for a moment, a barrel roll may be performed with very little g.
The usual mistake made by novices is not getting the nose high enough at the start. This leads to a buried nose scenario in the second half, and that's when it goes wrong.
Trust me here. I am a retired QFI (RAF) and aerobatics pilot with three trophies to my name, one of them very prestigious.
The usual mistake made by novices is not getting the nose high enough at the start. This leads to a buried nose scenario in the second half, and that's when it goes wrong.
Trust me here. I am a retired QFI (RAF) and aerobatics pilot with three trophies to my name, one of them very prestigious.
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Aerobatic engines have scavenger pumps in the sump which then take it to a tank which means when you play silly sods a supply of oil is maintained to the bits that need it.
I personally fly the Robin R2160 (and, coincidentally, so does Mark1234). As far as I know the engine is completely identical to what's mounted on, say, a DR400-160 with the one exception and that is that there's a cup or something to prevent the oil from leaking out through the breather pipe when inverted. (Still, anything over 5 quarts is chucked out anyway.) Even the dipstick is in the same place, so I assume this engine has a wet sump too.
When pulling positive Gs (the airframe is certified to 6 G) there are no limitations whatsoever. As far as the manufacturer is concerned you can pull that all day. So I assume the oil pump is fully capable of supplying the engine with sufficient oil even in relatively high-g manoeuvers.
The catch with this engine is of course the negative Gs. The wet sump means that the oil pump will run dry, no longer supplying oil to the engine. Because of this all inverted manoeuvres are limited to 20 seconds or less - we use 10 seconds for additional safety margin.
So what triggered my post was your suggestion that during positive G manoeuvres (loop, barrel roll) in a PA-38 you would shag the engine because the oil pump would not cope. I think this is incorrect. But you would definitely shag the engine in a relatively short time with negative G manoeuvers.
or even sit in one while someone else does.
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Ric00....
i'd like to see where you got that info...
i instructed in a PA38 for 15 years....we spun it but thats it....
...(four point harness permitted in our jurisdiction.....)
primary rule in this or stalls..( but used to invite the student to do it)....do'nt look at the tail......!!!!!!!
i'd like to see where you got that info...
i instructed in a PA38 for 15 years....we spun it but thats it....
...(four point harness permitted in our jurisdiction.....)primary rule in this or stalls..( but used to invite the student to do it)....do'nt look at the tail......!!!!!!!
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Just think about all the people who will be questioning your intentions in club houses all over the country and on here when the AAIB report is published if you try something silly and bugger it up.