homebuilt safety

Statistically, takeoffs are more lethal than landings, even though
landings take more skill for a good "show". During initial takeoff a
typical aircraft is just above stall and climbing. An engine failure
on takeoff near ground could easily put you in a stall where recovery
is slim and nose down is more probable - and you "collide" with the
earth. In a conventional aircraft I prefer rotating at a higher speed
than customary, and get the extra speed edge to glide down to earth in
case of engine failure.

In landing problems landing speed itself is not much of a factor
unless you collide with something. Aside from fire or tiping over
remote possibility, higher landing speed along the runway simply
results in a longer slide. Recently an individual came down in a storm
and busted their landing gear on touchdown with same type of aircraft
as mine and resulted in no injury and relatively little damage to
aircraft. This was inspite of the fact that the touchdown speed is 90+
mph.

--------------------------------------------
Paul Lee, SQ2000 canard: www.abri.com/sq2000

"Pete Schaefer" wrote in message news:Btqpc.53022$536.9082680@attbi_s03...
Landing speeds are a big driver for the amount of injury. I think that the
FAA has a lot of data on this. Can't think of a reference off-hand, but you
can search the NTSB site. But anyway, here's the math: KE = (1/2)mv^2. The
basic conclusion is that accidents occuring at lower landing speeds do less
damage. This was a driver for the design of the RV series aircraft. If you
want safety, get something with STOL capability, make sure there's nothing
in the cockpit that's going to smack you in the back of the head if you
screw up, then practice, practice, practice (with an instructor until you
feel confident).....then practice some more. Avoid low-level aerobatics
until you're a really ****-hot pilot.

You really need to forget about structural protection in a home-built. The
key is to prevent (by flight procedure, pilot skill and knowledge, and by
appropriate vehicle design) accidents from happening in the first place.

Pete
[RV-8A in the planning stages....new shop under construction]

"anonymous coward" wrote in message
news
I agree this sounds impossibly fraught. What I would like (ideally) would
be the results of something akin to the car-crash tests that show how the
test-dummies fared in various scenarios - e.g. side impacts etc... I saw a

On Sun, 16 May 2004 16:42:03 +0100, anonymous coward
wrote:

On Sat, 15 May 2004 15:14:41 +0000, Pete Schaefer wrote:

Landing speeds are a big driver for the amount of injury. I think that the
FAA has a lot of data on this. Can't think of a reference off-hand, but you


I like the look of the IBIS (http://www.junqua-aircraft.com/) and I'd
prefer to build in wood. But the more I read, the less good an idea the
Ibis seems (fast landing speeds - only a few complete, so perhaps more
prone to 'bugs' than established designs such as the LongEZ and friends).

china plate (mate) if you want a very good economical wood design then
the Corby Starlet has a lot to offer. it is aerobatic to 4g. has
something like 33 years of safe proven use. its a design that has
never had an AD issued for it. the owners I know just love them.
very few have ever been pranged.

recommended engine is a jabiru 2200cc. delivers about 11litres per
hour fuel burn and can see the starlet to Vne in level flight.

btw it is a real aeronautical engineer designed aeroplane.
plans are about $aus200. 'bout $US150.

do a web search for "Corby Starlet"

Stealth Pilot

On 16 May 2004 18:22:21 -0700, (Paul Lee)
wrote:

:This was inspite of the fact that the touchdown speed is 90+
:mph.

Oh, sweet Jesus, I hope you're kidding. What empty weight and CG
range are you running?

anonymous coward wrote:


I agree this sounds impossibly fraught. What I would like (ideally) would
be the results of something akin to the car-crash tests that show how the
test-dummies fared in various scenarios - e.g. side impacts etc... I saw a
documentary about car-safety a few years ago, that mentioned that the
technology of crumple-zones and reinforced passenger compartments was
originally developed for WWII naval aircraft. Don't homebuilt designers
think about features such as these? Or would they help in so few scenarios
that it's an irrelevance?


John Dyke did. The front page of my websitehas a 3D CAD rendering of
the cockpit with a pilot seated. Note the comparatively HUGE crumple
zone in front and to each side enjoyed by the pilot compared to most
designs. For most designs, trying to get this sort of crumple zone
would make the craft extremely safe...'cause it'd be so heavy that it'd
never fly!!

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber

On Sat, 15 May 2004 15:09:43 +0100, anonymous coward
wrote:

I agree this sounds impossibly fraught. What I would like (ideally) would
be the results of something akin to the car-crash tests that show how the
test-dummies fared in various scenarios - e.g. side impacts etc... I saw a
documentary about car-safety a few years ago, that mentioned that the
technology of crumple-zones and reinforced passenger compartments was
originally developed for WWII naval aircraft

I'm pretty surprised to hear about this. My knowledge, such as it is,
about WWII fighters in general, and Navy fighters in particular is
that they were either designed with production/armament in mind or
aerodynamics (speed or maneuverability) in mind, but building
"crumple-zones" wasn't a priority, if they even knew of the concept in
1940.

This is especially true for the Navy fighters which had to do all the
things the non Navy fighters did, but in addition they had to crash
repeatedly on the carrier deck in what the Navy laughably calls
"landings". Needless to say, they were supposed to be in one piece
after every landing, which means that they ended up heavier in general
than the typical same size Army fighter.

It just happens that in a violent crash, the outer appendages will
tend to shed from the airplane. I've seen footage of an F6F botching
the landing and colliding with the island, after which the only thing
left intact was the cockpit, with the pilot still in it. But I doubt
that Grumman planned on guys hitting the island when they designed the
airplane, it's just that it shed all it's heavy pieces during the
oblique impact. The pilot was extremely lucky he did not hit head on:
he would have been the crumple zone.

Corky Scott

anonymous coward wrote in message e...

I feel more and more drawn towards the idea of building a wooden 3-axis
microlight - some of them seem to have quite short build times, and as you
say, slow landing speeds have got to be a good thing.

Have a look at the Evans VP-1 "Volkplane" or the Bowers "FlyBaby".
The VP is simpler, but the FB has a better look IMO. Both designs
date from the 60's and have scores of examples flying with thousands
of hours accumulated. Both have active builder/pilot groups on Yahoo.
Ron Wanntaja maintains an excellent website at www.bowersflybaby.com

Ditto the other comments in this thread - in any aircraft the
component most susceptible to catastrophic failure is the nut behind
the stick.

Good luck to you!

--Corrie, gettin' ready to cut wood for a FlyBaby

On Mon, 17 May 2004 13:29:04 -0400, charles.k.scott wrote:

On Sat, 15 May 2004 15:09:43 +0100, anonymous coward
wrote:

I agree this sounds impossibly fraught. What I would like (ideally) would
be the results of something akin to the car-crash tests that show how the
test-dummies fared in various scenarios - e.g. side impacts etc... I saw a
documentary about car-safety a few years ago, that mentioned that the
technology of crumple-zones and reinforced passenger compartments was
originally developed for WWII naval aircraft

I'm pretty surprised to hear about this. My knowledge, such as it is,
about WWII fighters in general, and Navy fighters in particular is
that they were either designed with production/armament in mind or
aerodynamics (speed or maneuverability) in mind, but building
"crumple-zones" wasn't a priority, if they even knew of the concept in
1940.

The argument, provided I'm not confabulating it, was that there was a
shortage of combat pilots so it was worthwhile building a 'plane that
let them live to crash again.

This is especially true for the Navy fighters which had to do all the
things the non Navy fighters did, but in addition they had to crash
repeatedly on the carrier deck in what the Navy laughably calls
"landings". Needless to say, they were supposed to be in one piece
after every landing, which means that they ended up heavier in general
than the typical same size Army fighter.

It just happens that in a violent crash, the outer appendages will tend
to shed from the airplane. I've seen footage of an F6F botching the
landing and colliding with the island, after which the only thing left
intact was the cockpit, with the pilot still in it. But I doubt that
Grumman planned on guys hitting the island when they designed the
airplane, it's just that it shed all it's heavy pieces during the
oblique impact. The pilot was extremely lucky he did not hit head on:
he would have been the crumple zone.

The footage I remember was of a prop-plane coming in to land very heavily.
The entire aircraft snapped in two behind the pilot compartment. Suffice
to say, Google can't find any link between "crumple-zone" and "aircraft
carrier" so it's possible my memory has gone cloudy.

AC

Richard Riley wrote in message . ..
On 16 May 2004 18:22:21 -0700, (Paul Lee)
wrote:

:This was inspite of the fact that the touchdown speed is 90+
:mph.

Oh, sweet Jesus, I hope you're kidding. What empty weight and CG
range are you running?

Don't think you are informed about canards - especially faster ones.

And there is no need to trivialize/misuse Jesus name, it is revered by me
and many others.

Paul Lee.

Paul Lee wrote:

Don't think you are informed about
canards - especially faster ones.

If you'd care to place a wager on
Richard 'Renaissance' Riley's knowlege of canards
a good portion of the newsgroup would probably take
you up on it g

So, like he asked, at what weight do you use a *touchdown*
speed in excess of 90 knots? Heck, what's your tire speed?
That's pretty fast for a well-designed GA canard unless it's
pretty freakin' heavy.

Dave 'sssssmokin' Hyde

On 17 May 2004 18:02:56 -0700, (Paul Lee)
wrote:

:Richard Riley wrote in message . ..
: On 16 May 2004 18:22:21 -0700, (Paul Lee)
: wrote:
:
: :This was inspite of the fact that the touchdown speed is 90+
: :mph.
:
: Oh, sweet Jesus, I hope you're kidding. What empty weight and CG
: range are you running?
:
on't think you are informed about canards - especially faster ones.

I think I am.

:And there is no need to trivialize/misuse Jesus name, it is revered by me
:and many others.

It is my profound wish that you delay meeting him as long as possible.

The closest canard type to yours is the Cozy Mk 4 - the same planform
and airfoils, the same engine, the same number of seats at the same
fuselage stations. Performance-wise, the only big airframe difference
is the retractable main gear (and the horrible back end of the SQ's
cowl.)

Generally speaking, a Mk 4 will touch down at about 75 mph - 100
downwind, 90 base, 80-85 on short final. Significant forward CG (in
the 98" range) heavy gross weigh or cross winds might add 5 mph or so.

Those are about the same numbers most people use for a Long EZ with a
big engines. Berkut with a 540 is a bit faster, it will touch down
closer to 80. A light, small engine EZ will touch down a bit slower,
in the 65-70 mph range.

The difference between a 75 mph touchdown and a 90+ mph touchdown is
significant. It's a 44% + increase in your momentum. I know the
Matco W50L's are good, but do you want to get rid of that much of the
margin?

Low speed handling is significantly improved by trailing edge fences,
you may want to look into them.
http://www.lsecorp.com/KlausInfo/Flowfence.htm