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About to build a Harmon Rocket I

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rentiap

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Greetings:
I am about to pull the trigger and order the parts to build what I believe to be "essentially" a Harmon Rocket I using a RV-3b instead of an RV-4 for the foundation.

((actually this may just be a hopped up RV-3 with mods))

I have only found 2 pictures and what looks like what the late Pete Albrecht (sorry to hear that he has passed) was flying in the video that is posted of Harmon Rocket I's.

I prefer the slimmer front cowl of the RV-3 with cheeks, with fast-back rear turtledeck,
than the wider squared out look of the Rocket II, and am going to stay with a lighter weight stroked out IOX-340S (185-190 horse) apposed to going with the heavier IO-360, or the HR-III and much heavier IO-540.

I would like to shoot for an empty weight of 775 lbs, as apposed to the empty weight of 1080 lbs of the Rocket III.
I have not found very much info on the few HR-I's that have been built.

I am figuring that I will be needing to setback the cockpit for CG.(like the HR-III)

Does anybody have any information that could help in figuring out this setback before I actually start ordering the parts?

Any discussion and info is appreciated.
Thank you,
Geodfreid.
 
Although it looks like you have discounted the RV4 as a foundation I still think that a clipped wing, single place RV4 would give you a more versatile aircraft. By that I mean you would be able to carry some baggage and have more engine options. It would retain the cowl cheeks that you like and with a raised turtle deck with seating towards the rear it would look hot.
 
Rocket I

John Harmon and I went to high school together and my Rocket II is S/N 2 and his prototype is S/N 1. I'm not sure I remember the exact sequence of the Rocket I's evolution, but John did build two of them concurrently - one for the "sponser" - Jim Irwin (not AC Spruce guy), and one for himself as payment. This was back in the early to mid 1980's. They were essentially a standard -3 with a "pumped up" motor and a raised turtleback, I don't recall any change of seating location for CG reasons as all the parts and pieces were installed in the original locations.

You may or may not be aware, but Van made a drawing of the aft raised turtleback for the -3 back in 1984 - "Fuselage - Aft Fastback" Drawing #22, with upgrades by Sid Goldin in June of 1997. It provides the "callout" for the parts needed to turn a standard 3 into a razorback version. I have one of the few copies that are still floating around out there in space.

I am currently about 30% through my own -3 build, and am incorporating some of the upgrades that Van integrated into the design of the -4. I built (and flew for 15 years) a 4, and have noted the benefit of these changes from that airplane. When finished this airplane will feel like a single place RV4, but in the confines of a -3 "body".

If you want (need) any additional info regarding the above - give me a call at (559)816-0433.
 
I have 100hrs on my -3 and its a great airplane. Current project,a single seat, clipped wing, 4 cylinder -4.
I've used the stock -4 motor mount and gear legs and the fwd fuse is the stock width at the bottom but 33 inches at the top. The upper longerons are straight from the seatback to the firewall. Uing the stock "cheeked" cowl as a start and "most" of the cheek will blend into the wider firewall. I believe the H1's were similar, keeping(hopefully) the slender/less blunt/faster stock nose.
Using the stock rear seat back position, the HR's are about 4" further back.
About 20' span,late model elevator balances with clipped stab,revised aft fuse bulkhead that matches the rudder width, a lot more room for systems, battery on the firewall and a C/S prop makes the C of G work and you've got the deeper/stronger spar of the -4.
My -3 is 760lbs so aiming for 900lbs this one.
Mike
 
I would consider the CC-340 if they will sell you one.

Cub Crafters has done a lot of work on the 340. They pump it up to 180hp and although they put limits on the duration and allowable RPM's at a given altitude, I believe it is striclty to keep the SS in the Light Sport category. I believe you could run that engine all day at its fully rated HP.
They have taken a lot of wieght out by designing their own light weight fabricated sump, electronic ignition, and probably a few more things.
I do not beleive you could find a better lower wieght engine.
There was some talk about making this engine available to the public. I am not sure if that talk ever went forward or what the ultimate price of that product would be. CC is not a low price industry leader....:D
We have the good fortune of having Randy (Tardy/Splash) Lervold working for them. Nobody knows RV's like Randy and he would be the one to start with if you wanted to pursue this further. He may even still lurk on this forum.
You can take the pilot out of the RV but you can't take the RV out of the pilot. Ha!
 
Sounds like you just want a fastback -3. No need to stretch it, as there is plenty of room n the cockpit. A friend of mine built one and I flew it a few times...what a fun, nice flying, economical airplane. He did the raised turtledeck per the plans mentioned above and built a custom canopy frame and had a bubble blown for it. Sadly he crashed it and and eventually died from his injuries.
 
Hmmm??? to b-4? or to-3b?

Thanks for your comments Tom;
I have not completely discounted using the -4 for the foundation for this project.
There are many considerations that must be considered.
And of course I don't want to limit myself to engine options.
Also if I use the -4 as the foundation there is also the option for larger fuel cells.
And with the clipped -4 wing possibly a stronger wing. then the -3b wing.
Which is a better airfoil?
The thinner 23012 of the -3b with new internal structure @ 19ft 11inches?
Or the slightly thicker 23013.5 -4 clipped to 20 ft.?
Does anyone have an opinion on which is the stronger more efficient wing?
Lots to consider here.
Cheers,
Geodfreid.

Although it looks like you have discounted the RV4 as a foundation I still think that a clipped wing, single place RV4 would give you a more versatile aircraft. By that I mean you would be able to carry some baggage and have more engine options. It would retain the cowl cheeks that you like and with a raised turtle deck with seating towards the rear it would look hot.
 
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Hi David:
I am not sure I could have asked for someone any closer to knowing about the HR-1 then you. I was hoping for someone like you to reply with first hand knowledge. I am sure I will be contacting you in the very near future.and hope to bend your ear a bit.
I was not aware that Van had "made a drawing of the aft raised turtleback for the -3 back in 1984 - "Fuselage - Aft Fastback" Drawing #22, with upgrades by Sid Goldin in June of 1997". And provides the "callout" for the parts needed to turn a standard 3 into a razorback version.this is great news
I have contacted John Harmon ,and he stated that the rear bulkheads he makes for the rocket II will work to make the raised turtleback if used on the -3. I am sure it wouldn't be just a slip in and go,,,some massaging I am sure would be required,,,But that's Kewl.
Thanks,
Geodfreid


John Harmon and I went to high school together and my Rocket II is S/N 2 and his prototype is S/N 1. I'm not sure I remember the exact sequence of the Rocket I's evolution, but John did build two of them concurrently - one for the "sponser" - Jim Irwin (not AC Spruce guy), and one for himself as payment. This was back in the early to mid 1980's. They were essentially a standard -3 with a "pumped up" motor and a raised turtleback, I don't recall any change of seating location for CG reasons as all the parts and pieces were installed in the original locations.

You may or may not be aware, but Van made a drawing of the aft raised turtleback for the -3 back in 1984 - "Fuselage - Aft Fastback" Drawing #22, with upgrades by Sid Goldin in June of 1997. It provides the "callout" for the parts needed to turn a standard 3 into a razorback version. I have one of the few copies that are still floating around out there in space.

I am currently about 30% through my own -3 build, and am incorporating some of the upgrades that Van integrated into the design of the -4. I built (and flew for 15 years) a 4, and have noted the benefit of these changes from that airplane. When finished this airplane will feel like a single place RV4, but in the confines of a -3 "body".

If you want (need) any additional info regarding the above - give me a call at (559)816-0433.
 
Hi Mike:
Sounds like you might already be doing just what I was thinking of doing,,,Do you have any Pics of this fine project?

I have 100hrs on my -3 and its a great airplane. Current project,a single seat, clipped wing, 4 cylinder -4.
I've used the stock -4 motor mount and gear legs and the fwd fuse is the stock width at the bottom but 33 inches at the top. The upper longerons are straight from the seatback to the firewall. Uing the stock "cheeked" cowl as a start and "most" of the cheek will blend into the wider firewall. I believe the H1's were similar, keeping(hopefully) the slender/less blunt/faster stock nose.
Using the stock rear seat back position, the HR's are about 4" further back.
About 20' span,late model elevator balances with clipped stab,revised aft fuse bulkhead that matches the rudder width, a lot more room for systems, battery on the firewall and a C/S prop makes the C of G work and you've got the deeper/stronger spar of the -4.
My -3 is 760lbs so aiming for 900lbs this one.
Mike
 
Is there a more efficient way?

Hey Jon: Thanks for the heads up on Cub Crafters.
Maybe Randy will give his 2cts worth? :D;)

Should I be restricting myself to the smaller size of the stroked out IO-340?
What if I decide to go for 200 HP.
What would be the lightest most efficient way to make 200+HP?
Just more questions ?

Cheers,
Geodfreid.

Cub Crafters has done a lot of work on the 340. They pump it up to 180hp and although they put limits on the duration and allowable RPM's at a given altitude, I believe it is striclty to keep the SS in the Light Sport category. I believe you could run that engine all day at its fully rated HP.
They have taken a lot of wieght out by designing their own light weight fabricated sump, electronic ignition, and probably a few more things.
I do not beleive you could find a better lower wieght engine.
There was some talk about making this engine available to the public. I am not sure if that talk ever went forward or what the ultimate price of that product would be. CC is not a low price industry leader....:D
We have the good fortune of having Randy (Tardy/Splash) Lervold working for them. Nobody knows RV's like Randy and he would be the one to start with if you wanted to pursue this further. He may even still lurk on this forum.
You can take the pilot out of the RV but you can't take the RV out of the pilot. Ha!
 
:D Yes you just maybe correct..sure sounds like the easiest way to get where I am trying to get,,,Sad! sorry to hear about your friend:(
Sounds like you just want a fastback -3. No need to stretch it, as there is plenty of room n the cockpit. A friend of mine built one and I flew it a few times...what a fun, nice flying, economical airplane. He did the raised turtledeck per the plans mentioned above and built a custom canopy frame and had a bubble blown for it. Sadly he crashed it and and eventually died from his injuries.
 
OK, Here is what I believe will be the deciding factor of how I build this Rocket; The property that I am buying has an area that will allow me to build an 800 foot runway..800and one foot starts hitting a fence then runs into the neighbors barn. So actual usable surface is about 780 feet.
Runs in a north to south direction with a rise of about 6 feet from the start of the north end to the south.
Trees will have to be cut down at the north end and power lines will have to be buried to make this runway work.
I don't believe takeoff would be a problem downhill-south to north with any of the rocket options.

The landing seems to be what could be the problem.
Weather it is a HR-1 using the RV-3b platform 185 horse IOX-340s @approximately 250 pounds and a total weight of 775 pounds FP wood prop and advertised stall speed of 51 mph, (landing length by Van's of 350 feet) (30 gallon tanks),,,( I plan on using the 3 blade 151 CS series prop by Whirlwind)so that should help in the slow down
Or building the HR2 as a pilot only,no passenger, with the clipped RV-4 wings raised rear fastback and RV-4 tail feathers with the same engine prop selection as the HR-1 build.
(Front cowl and width will stay standard RV-3/4)


RV-4 is advertised to be able to land @ 300 feet with a 48 mph stall speed (of course with full length wings)
The advertised stall speed (by Harmon)of the HR2 is 55 mph. that is of course with the added weight of the IO-540 on the nose of the HR2 and empty weight of 1200 pounds,,I have not found any quotes of short strip landings.

I am leaning toward using the RV-4 as the platform for my build because of,
The stronger wing(and even stronger if clipped to HR2 length)(HRIII length is even shorter and advertised stall speed is even higher @ 58 mph)
Larger fuel tanks(42 gallons as apposed to the 30 gallons of the 3b)
Electric flaps and elevator options available on the -4 that is not available as option on -3
Maybe better sets of plans and more support from both the RV and HR2 community since there are many more builders out there then there are HR1 builders.

If I go with the RV-4 platform, single pilot only cockpit,raised rear fastback,250 pound IOX 340s engine,CS 3 blade whirlwind 151 prop(28 pounds)42 gallon tanks, clipped HR2 -4 wings and lots of practice on longer runways.
Am I going to be able to stop this plane on an 780 foot uphill, north to south asphalt runway????

Or will I have to leave the wings @ UN-clipped -4 length?

Thanks,
Geodfreid.
 
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For this application you are going to need the longer wing. I hope you have a back up airport close to this strip as there will be times when it is not safe to land there. I am not a good enough pilot to take my rocket into an 800 foot runway.
 
I second the above comments. Our insurance rates are bad enough already... please don't!!!

While a Rocket will easily take off in that distance (on most days), you'll quickly find out what the fence is made of on most landings... or you'll quickly find out how to repair bent gear legs, cracked engine mounts, and propellers.

Not only does an 800' strip offer no room for error... it simply offers NO room.:eek:
 
You never told us you were trying to operate your Rocket from an aircraft carrier. Maybe arresting cables and a big tail hook needs to be incorporated
 
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Hi Geofried,

You have an ambitious plan, and I hope it goes well for you.

What kind of flying experience do you have up to now?
 
Hello prporter:
No I don't have any tail wheel time. "YET" but hope to start getting as much as possible, real soon.
The fact is that I flew quite a bunch many years ago,,,then caught the racing bug, about twenty years ago which took up all my time fabricating and racing with 700 plus horsepower and learning as much as possible about ground effects and how to keep a car glued to the ground at the same time not being to well stuck, which would cause us to slow down,and also chopping,channeling and sectioning more street cars and trucks than I can now remember,,,,now it is time for me to get back off the ground away from the 2D and back into the 3d of flying,
I have not flown much for many years and do not have my own plane now,,,,,,that is why I am going to do this project,,,,I can do and build anything!
But I never just jump into a project before researching and having it all built in my head before I touch any parts.
I've gone 220 on the ground been upside down , spun every which way, and because of all the safety features built into those race cars ,,I am still in one piece, and have never been severely injured,,,now it's time to get into the air,but this time I will intentionally be getting upside down and spinning,,,Ha!
Thanks for being interested and asking.
Cheers,
Geodfreid.
Geodfried,

What are you flying now? Do you have tail wheel time?
 
780' is just a stamp on the ground. Taking off will be no problem on a std day but try on one of those high denlsity days and you are askinf for trouble. For your landing, it is too short period.

Someone said, buy a piper cub and fly it to where your harmon will be hangared....not a bad advise at all....

...i noticed you mentioned some motorsport carreer. Where at? F1, Indy, le mans series, etc? You mentioned ground efects......we have here at vaf the same kind of gear head crowd in some.....Lots of fighter pilots, pro car racers, pro motorcycle racers, aerobatic pilots, etc......Me, i am ex fim bike racer and aerobatic wanna be national competitor
 
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OR

C)incorporate the F1 Evo slotted flaps.:cool:

Not sure those are going to help you. Due to the weight of the Rocket, you have to carry a specific amount of speed to arrest the rate of descent. By the time you flare, you will chew up that distance in nothing flat. Add a little dew to the grass and you are out of options.
 
RV4 landing at Ladybank Field

Search you tube for "RV4 landing at Ladybank Field"
Also "Supercub landing at Ladybank Field"
and "Leaving the nest"

A rocket won't stop shorter than a 4 unless you replace the tailwheel with a cultivator shovel.

Cheers!
 
Search you tube for "RV4 landing at Ladybank Field"
Also "Supercub landing at Ladybank Field"
and "Leaving the nest"

A rocket won't stop shorter than a 4 unless you replace the tailwheel with a cultivator shovel.

Cheers!
LOL!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!:D:D:D:D:D:D:D
 
Geodfreid,

I hope your getting the point that what your suggesting is not really a good idea.

We do not want you to become another avoidable accident statistic.
 
Hello prporter:
No I don't have any tail wheel time. "YET" but hope to start getting as much as possible, real soon.
The fact is that I flew quite a bunch many years ago
Geodfreid.

Hi Geodfreid,

No one can say you don't have passion and ambition, which are the important ingredients needed to complete an aircraft kit.

The rockets are wonderful planes, and will serve a pilot well for many missions, but respectfully I think you might be trying to squeeze blood out of the proverbial turnip. To make that landing would require every aspect of your flight, let alone your skills, to be absolutely perfect every step of the way with no exceptions. I think even Captain Sullenberger would abort that landing if
there was one thing not "spot on". This would be an accident report just waiting to be written up.

"A superior pilot uses his superior judgement to avoid situations that would
require use of his superior skills."

"Aviation in itself is not inherently dangerous, but terribly unforgiving of any carelessness, capacity, or neglect." Slightly paraphrased.
 
Not sure those are going to help you. Due to the weight of the Rocket, you have to carry a specific amount of speed to arrest the rate of descent. By the time you flare, you will chew up that distance in nothing flat. Add a little dew to the grass and you are out of options.

Do people actually read the threads that they post to? or do they just make comments from seeing a couple of words that stand out to them?

As far as the weight of "the rocket' that I am proposing to build,,,I am looking at almost 500 pounds less gross weight, and about 300 pound less empty weight then the advertised weights of the F1 Evo,

If you read my earlier post you would see that I had the word asphalt in there.
This will be either an asphalt or concrete runway.

Add a little dew to what grass???????I quit drinking that mountain dew many years ago.. (Is some one smoking too much of that grass)???
 
Smoking grass, drinking whatever you want, I still think it's crazy!! Im no expert by any means but I really think you should look into a quicksilver or maybe a CGS hawk for your proposed runway. I used to own an avid flyer, maybe something of that type will fit your needs.
 
can I not believe what is posted on other threads?

http://www.vansairforce.com/community/showthread.php?t=68133&page=5
Originally Posted by F1 Boss
"For the low speed end, the airfoil we are using is very aggressive, as long as you don't mind the pitch attitude! It is possible to get an Evo down and stopped in less than 300', but it takes practice, and a good breeze."
Is it just the "aggressive airfoil" and nothing to do with the slotted flaps?
Or am I to believe that what is posted on other threads and Van's website is just hot air?

Please forgive me (everyone posting and reading to this forum)
It is not my intention to start a flame war here or to step on any ones toes.
I am here to try and glean as much information as possible as to what can actually be done with an airframe in whatever configuration that is best possible suited to the property that I am using.


Originally Posted by SpaYellowNsx Don't fly much, do you...?
Yes ,,,if you had read through the thread and read what I posted to prporter @post #24 you would have read that it has been some 20 years since I have been consistently in the air.,,,, I am here to learn..
Cheers,
Geodfreid.
 
http://www.vansairforce.com/community/showthread.php?t=68133&page=5
Is it just the "aggressive airfoil" and nothing to do with the slotted flaps?
Or am I to believe that what is posted on other threads and Van's website is just hot air?

Please forgive me (everyone posting and reading to this forum)
It is not my intention to start a flame war here or to step on any ones toes.
I am here to try and glean as much information as possible as to what can actually be done with an airframe in whatever configuration that is best possible suited to the property that I am using.


Yes ,,,if you had read through the thread and read what I
posted to prporter @post #24 you would have read that it has been some 20 years since I have been consistently in the air.,,,, I am here to learn..
Cheers,
Geodfreid.

Then let's hope that you learned that a 780 ft runway with trees at 800 ft is a ticket to the hospital, if you are lucky.
 
RV 6 crashes into tractor

You tube "RV 6 crashes into tractor":eek: This might be what Randy meant about a little dew in the grass.

Time to lighten this up a bit.... The 2 best you tube flying videos of all time could be "How to impress yer chick at a hot spring" & " Got Rocks"

Enjoy
 
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Geodfreid
At the beginning of this thread everyone was totally with you and supportive in your desire to build a unique airplane; We still are. I think it would be a wonderful unique project and feel free to contact me at any time regarding build issues.
When the 800 foot runway issue came up the wheels came off the discussion. With aircraft what is possible on the extreme end of the flight envelope is just not practical in day to day operations. It would be like have your absolute best car race each and every time you went to the track. The weather conditions, read wind down the runway, would have to be absolutely perfect. In 2000 hours of flight I can probably count on my hand how many times I have made the standards that you are setting for each and every flight.
Build the plane of your dreams but your runway choice for that plane will be a heart breaker.
 
Nice post Tom - thanks!

Folks, as a Moderator, I'm going to remind you that once you start name calling (asking folks if they are smoking grass?!), this is no longer a polite, civil discussion. You can talk facts, you can talk opinions, but the idea behind the VAF forums was that it not deteriorate into a place where folks are afraid to ask questions because they don't want to have to defend themselves.

Facts speak for themselves, and opinions are great, if you state them as such, then let the 20,000+ readers decide for themselves. You DO realize the 20,000+ people are looking at everything that you write, and judging you by what they read....don't you?

Paul
 
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