Harmon Rocket II questions

Does anyone here know much about the Harmon Rocket II?
I've been looking at it, and it concerns me in the fact that the
cockpit demensions look a little snug. It has enough room in width,
but the distance between the front and back seat seems too close, as
does the distance of the instrument panel from the front seat pilot.
Also, in looking at pictures of it, pilots seem to have their heads
right up against the top of the canopy. Is John Harmon a short guy?
I suspect it was designed by someone not so tall. I guess it would be
nice to go sit in one somewhere, but that's not always easy to find.
And I wonder if the wing is strong enough. His webiste says he did
nothing to the RV-4 wingspar to strengthen it. He only shortened it to
to reduce the bending moment on it, and reduced the rib spacing. Then
it says he sand bagged the wing to 6 G's. 6 G's isn't all that much
for an ultimate load test. So I'm a bit leery of the design. I wanted
to build one, but after doing a little research, I'm turned off by
what I've found out.

Earlier, Jason Grass wrote:

...Also, in looking at pictures of it,
pilots seem to have their heads right
up against the top of the canopy...

It's pretty typical when flying under a bubble canopy to add seat
padding until your head is right at the canopy crown, or at least as
close as comfortable. Glider pilots do that all the time to improve
visibility over the nose and downwards over the cockpit rail.
Taildragger pilots tend to do that to improve visibility during takeoff
and landing.

...Then it says he sand bagged the wing
to 6 G's. 6 G's isn't all that much for
an ultimate load test...

As much as I'm not a particular fan of the Harmon airplanes, I can't
say I'd do much different. I think that a good static test to a
_design_ limit of 6g should give you enough deflection data to
extrapolate the stresses above that to a reasonable degree of
confidence, and should leave you a flyable aircraft besides. I don't
think I'd do a static test to ultimate limit unless I was doing
something unorthodox or was expecting to manufacture finished aircraft.

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com/hp-24

"Jason Grass" wrote in message
...
Does anyone here know much about the Harmon Rocket II?
I've been looking at it, and it concerns me in the fact that the
cockpit demensions look a little snug. It has enough room in width,
but the distance between the front and back seat seems too close, as
does the distance of the instrument panel from the front seat pilot.
Also, in looking at pictures of it, pilots seem to have their heads
right up against the top of the canopy. Is John Harmon a short guy?
I suspect it was designed by someone not so tall. I guess it would be
nice to go sit in one somewhere, but that's not always easy to find.
And I wonder if the wing is strong enough. His webiste says he did
nothing to the RV-4 wingspar to strengthen it. He only shortened it to
to reduce the bending moment on it, and reduced the rib spacing. Then
it says he sand bagged the wing to 6 G's. 6 G's isn't all that much
for an ultimate load test. So I'm a bit leery of the design. I wanted
to build one, but after doing a little research, I'm turned off by
what I've found out.

Regarding the wing strength, I recall that Harmon "did the math" to confirm
the wing's strength at its reduced length. If I recall correctly, the
numbers said it was a 9+ G wing with the reduced span.

As far as cockpit dimensions go, it's a sport aircraft. The cockpits are
typically smaller than in spam cans. If you need a bigger cockpit, you
might look at an RV-8, although you'll lose a measure of performance.

KB

Jason Grass wrote:
Does anyone here know much about the Harmon Rocket II?
I've been looking at it, and it concerns me in the fact that the
cockpit demensions look a little snug. It has enough room in width,
but the distance between the front and back seat seems too close, as
does the distance of the instrument panel from the front seat pilot.
Also, in looking at pictures of it, pilots seem to have their heads
right up against the top of the canopy. Is John Harmon a short guy?
I suspect it was designed by someone not so tall. I guess it would be
nice to go sit in one somewhere, but that's not always easy to find.
And I wonder if the wing is strong enough. His webiste says he did
nothing to the RV-4 wingspar to strengthen it. He only shortened it to
to reduce the bending moment on it, and reduced the rib spacing. Then
it says he sand bagged the wing to 6 G's. 6 G's isn't all that much
for an ultimate load test. So I'm a bit leery of the design. I wanted
to build one, but after doing a little research, I'm turned off by
what I've found out.

I got a ride with John Harmon in his Rocket and it is a great airplane.
While I was not in the front seat the back seat has all kinds of room. I
am 6'3" tall and 200+lbs. and was not a bit crowded. One of my friends
just finished one and he is 6'+ and has a lot of room. You customize the
seats to fit your size. 6 G's is the load it could stand before it
could bend something, 9 G's is ultimate load. YOu might be turned off by
it but I would built one if I could afford one, but I will have to be
satisfied flying my 16 year old RV-6.

Jerry

On Mon, 31 Oct 2005 04:16:40 -0800, Jerry Springer
wrote:

Jason Grass wrote:
Does anyone here know much about the Harmon Rocket II?
I've been looking at it, and it concerns me in the fact that the
cockpit demensions look a little snug. It has enough room in width,
but the distance between the front and back seat seems too close, as
does the distance of the instrument panel from the front seat pilot.
Also, in looking at pictures of it, pilots seem to have their heads
right up against the top of the canopy. Is John Harmon a short guy?
I suspect it was designed by someone not so tall. I guess it would be
nice to go sit in one somewhere, but that's not always easy to find.
And I wonder if the wing is strong enough. His webiste says he did
nothing to the RV-4 wingspar to strengthen it. He only shortened it to
to reduce the bending moment on it, and reduced the rib spacing. Then
it says he sand bagged the wing to 6 G's. 6 G's isn't all that much
for an ultimate load test. So I'm a bit leery of the design. I wanted
to build one, but after doing a little research, I'm turned off by
what I've found out.

I got a ride with John Harmon in his Rocket and it is a great airplane.
While I was not in the front seat the back seat has all kinds of room. I
am 6'3" tall and 200+lbs. and was not a bit crowded. One of my friends
just finished one and he is 6'+ and has a lot of room. You customize the
seats to fit your size. 6 G's is the load it could stand before it
could bend something, 9 G's is ultimate load. YOu might be turned off by
it but I would built one if I could afford one, but I will have to be
satisfied flying my 16 year old RV-6.

Jerry

Thanks for the info ... I'm 6'2" so was naturally concerned with the
cockpit demensions. I'm flying a tandem homebuilt now with a 32" wide
cockpit, and it's comfortable. But the instrument panel is so close I
have to wear bi-focals to see it. The Harmon's panel looks even closer
to the pilot than my airplane's is. So I may need a new perscription
to see it :-)
9 G's as an ulimate load isn't all that much, but compared to spam
cans is plenty. Definitely not in the class of the unlimited acro
ships. But I don't do those types of maneuvers anyway, so would never
approach anything that would break the Rockets wing.
You know once I went through the FAA's exhibition hanger in Lakeland,
and the inspector was handing out accident info on homebuilts, and the
one plane that stood out among the rest in the list was the RV-3. It
had numerous wing spar failures, resulting in accidents. So I've
always felt the entire RV line has weak wings, since they are pretty
much similar in design. And there was an RV accident once involving
wing failure, and a fellow homebuilder I was talking to on the flight
line in Lakeland said he asked Van about that accident's cause, and
his reply was "I guess we'll never know". And that fellow told me "If
I were the designer of that line I'd sure as hell want to find out!"
He definitely didn't care for Van's answer to his question.
I guess aluminum just can't approach the strength in some of these
I-beam type of spars you see in the composite ships.

ive just got to respond to this.

1. the failures of RV-3 wings were fixed years and years ago, from what ive
been told it was not a design problem but a problem with the way people were
assembling the wing. Van redesigned it anyway, for added strength.
2. this my cousin knows someones brother that said---- crap, don't cut it.
Talk to Van. he will tell you exactly what you want to know. his web site
has all the details of the RV-8 wing separation and the testing that was
done after to re-prove the design.
3. check the FAA data base yourself, I have and there has NOT been one
in-flight failure of a wing on a RV-4.
4. with over 3000 planes flying and several thousand more in construction,
stating that the RV line has weak wings, is pure horsesh--.

yes , I am biased, but I will put my RV-4 up against anything out there. Van
is one of the most honest and talented designers out there and his success
more than proves his designs.

R. Burns
RV-4 N82RB


0 You know once I went through the FAA's exhibition hanger in Lakeland,
and the inspector was handing out accident info on homebuilts, and the
one plane that stood out among the rest in the list was the RV-3. It
had numerous wing spar failures, resulting in accidents. So I've
always felt the entire RV line has weak wings, since they are pretty
much similar in design. And there was an RV accident once involving
wing failure, and a fellow homebuilder I was talking to on the flight
line in Lakeland said he asked Van about that accident's cause, and
his reply was "I guess we'll never know". And that fellow told me "If
I were the designer of that line I'd sure as hell want to find out!"
He definitely didn't care for Van's answer to his question.
I guess aluminum just can't approach the strength in some of these
I-beam type of spars you see in the composite ships.

On Mon, 31 Oct 2005 15:39:13 GMT, "comanche driver"
wrote:

ive just got to respond to this.

1. the failures of RV-3 wings were fixed years and years ago, from what ive
been told it was not a design problem but a problem with the way people were
assembling the wing. Van redesigned it anyway, for added strength.
2. this my cousin knows someones brother that said---- crap, don't cut it.
Talk to Van. he will tell you exactly what you want to know. his web site
has all the details of the RV-8 wing separation and the testing that was
done after to re-prove the design.
3. check the FAA data base yourself, I have and there has NOT been one
in-flight failure of a wing on a RV-4.
4. with over 3000 planes flying and several thousand more in construction,
stating that the RV line has weak wings, is pure horsesh--.

yes , I am biased, but I will put my RV-4 up against anything out there. Van
is one of the most honest and talented designers out there and his success
more than proves his designs.

R. Burns
RV-4 N82RB

The problem is, wing failures are not something builders and kit
manufacturers like to talk about. So the fact that the RV-3 wings were
fixed years ago hasn't been that widely publicized. So there are still
a lot of fears of those accidents. It's good to hear it's been fixed.
You won't find a word about that on Van's site. But being in the
business to sell kits, If I were in that position, I would just as
soon not bring that up either. So when the FAA hands out accident
reports showing RV-3 wing failures, there's no place to turn to that
has just as open information showing the problem has been fixed.
I would seem that ordering a spar built by Phlogiston would eliminate
builder inconsistancies and improve the saftey margin, and assuming
the design is good, the wing should be as good as one on a certified
plane. I might ask, where is the written information that tells about
the RV-3 wings being fixed? Certainly no place I've been able to find.
I've got the Sport aviation on CDrom, are there any issues that relate
to the fixes? Heck, your saying they've been fixed don't cut it
anymore than they guys on the flight line at Lakeland. So don't knock
what they say just because you are flying in an RV and don't want to
entertain the idea that maybe your wing "ain't so great" since your
rear end is at stake.

On Mon, 31 Oct 2005 15:39:13 GMT, "comanche driver"
wrote:

ive just got to respond to this.

1. the failures of RV-3 wings were fixed years and years ago, from what ive
been told it was not a design problem but a problem with the way people were
assembling the wing. Van redesigned it anyway, for added strength.
2. this my cousin knows someones brother that said---- crap, don't cut it.
Talk to Van. he will tell you exactly what you want to know. his web site
has all the details of the RV-8 wing separation and the testing that was
done after to re-prove the design.
3. check the FAA data base yourself, I have and there has NOT been one
in-flight failure of a wing on a RV-4.
4. with over 3000 planes flying and several thousand more in construction,
stating that the RV line has weak wings, is pure horsesh--.

yes , I am biased, but I will put my RV-4 up against anything out there. Van
is one of the most honest and talented designers out there and his success
more than proves his designs.

R. Burns
RV-4 N82RB

I dug a little deeper and found an excellent article in the Jan.1983
Sport Aviaton, pages 51-55. It was written by R.Van. and is quite
detailed and revealing about the 4 fatal RV-3 wing failure accidents.
It brings up a lot of little known issues pertaining to the FAA's
oversight of homebuilts. Such as the issuance of a GENOT against the
RV-3 prohibiting any aerobatics in them. I never knew the FAA could
issue such a rule against a homebuilt. Since they are supposed to be
51% built by the homebuilder, each one should be viewed as an
individual plane, not related to others. But apparently not in the
FAA's eyes.
On another note, the RV-3 is in my opinion the only really
good-looking RV design. Until the Harmon Rocket came along that is.
The rest of them are, well, lets say they don't get me enthused enough
to want to build one. But then, some builders are more interested in
other things. The RV-4 looks pretty good too, but seems small for 2
people.

On Mon, 31 Oct 2005 11:26:39 -0500, Jason Grass
wrote:

On Mon, 31 Oct 2005 15:39:13 GMT, "comanche driver"
wrote:

ive just got to respond to this.

1. the failures of RV-3 wings were fixed years and years ago, from what ive
been told it was not a design problem but a problem with the way people were
assembling the wing. Van redesigned it anyway, for added strength.
2. this my cousin knows someones brother that said---- crap, don't cut it.
Talk to Van. he will tell you exactly what you want to know. his web site
has all the details of the RV-8 wing separation and the testing that was
done after to re-prove the design.
3. check the FAA data base yourself, I have and there has NOT been one
in-flight failure of a wing on a RV-4.
4. with over 3000 planes flying and several thousand more in construction,
stating that the RV line has weak wings, is pure horsesh--.

yes , I am biased, but I will put my RV-4 up against anything out there. Van
is one of the most honest and talented designers out there and his success
more than proves his designs.

R. Burns
RV-4 N82RB

After some more research, I found another Sport Aviation article, in
the April 1998 issue, page 14, they report a total of 7!!! wing
failures in RV-3. Whew, I'm not stepping foot in one those things!
It seems after that one, Van offered the kit to fix the weakness for
free to anyone that hasn't had it done. Do you think that fix really
makes it safe? You know, it's not uncommon for a design to linger for
years that has a fatal flaw. Take the Questair Venture for instance.
Turns out that thing is an absolute deathtrap, but it sold for big
bucks for years, and I still see them for sale for high numbers. But I
was at Reno the year 3 of them were destroyed, one fatally, before
people finally started to see the light with that design.

Jason Grass wrote:
...
You know, it's not uncommon for a design to linger for
years that has a fatal flaw. Take the Questair Venture for instance.
Turns out that thing is an absolute deathtrap, but it sold for big
bucks for years, and I still see them for sale for high numbers. But I
was at Reno the year 3 of them were destroyed, one fatally, before
people finally started to see the light with that design.

Could you elaborate on that fatal flaw?

--

FF