[panhandler1956]

Well after getting great input on the RV-4 vs RV-8 I am now looking at RV-8 vs the Harmon Rocket - sorry guys, not trying to start a fight, but I am really struggling with this decision. Seems like you can build both for close to the same amount of money. Also I can't afford an F-1 Rocket QB or we wouldn't be having this conversation. I plan to build over 5+ year period to pay for the project so that might offset the complexity of the HRII.

Stuff I have identified:
RV-8
- much easier to build
- more builder support
- no chance of burning 20gph (good and bad)
- not as pretty as the HRII (IMHO)


HRII
- Fast
- Climbs like an elevator
- Hard to build with mixing 2 component manufacturers (3 in my case with F-1 parts too)
- Can build for about the same as an -8.


Any input is appreciated!

Brent

 

[kcpgm]

Consider insurance cost and resale


Ken RV-7 flying now painting i swear i can build a fusalage quicker then i can paint it Maine

 

[L.Adamson]

tail wheel?

I have a 6A. Chose the nosewheel because I thought it was more practical, and better looking on the ground, than the squatting 6.

But there is NO question in my mind; my preference would be the Rocket & preferably the F1, over all the RV's.

Just meaner & faster looking, as well as actually being faster; and a "tail dragger" as well!

 

[gmcjetpilot]

Mo Money

You did not mention cost. The HRII comes in a QB form via Team Rocket (F-1). However when all is said, kit, engine, prop the HRII is way more money. Nothing wrong with more money, just a fact. Now if you are an expert in finding an old RV-4 kit, used 540 and prop, than you can build a "cheap" Rocket, but new for new, the Rocket is more money.

As far as planes, both are fantastic, you can't go wrong. They are both RV's anyway. Rocket guys want to say it's not a wider, stretched RV-4 with a 540, but it is. Nothing wrong with that, the RV-4 is a fantastic plane.

Last is the engine vs. fuel burn. Many Rocket guys, one in particular say they get better fuel burn than a O320 or O360. That may be true, but you better have great discipline and be skilled at leaning, which we all should be and is not hard.

I am guessing at least $20K-$30K more for the Rocket.

 

[panhandler1956]

Great advice so far - keep it coming.

The insurance is definately higher on the Rocket from what I gather.

As for the build price, I would be trying to build it light - wallet wise and I have a supplier for inexpensive (if you can call it that) powerplants.

I totally agree with the fact that it is a modified RV-4 and in fact I like the idea of being attached to the RV series - what a wonderful group of very ACTIVE pilots! I actually started this quest in love with the -4 so this notion of a Rocket is perfect in that perspective - you can probably tell which way I am leaning.

I am pretty handy, have rebuilt a couple of non-riveted aircraft, but I'm a little intimidated by the mixin' and matchin' parts that is required to do an HRII. Can anyone comment on this aspect?

 

[f1rocket]

They are both RV's anyway. Rocket guys want to say it's not a wider, stretched RV-4 with a 540, but it is. Nothing wrong with that, the RV-4 is a fantastic plane.

In the same way your Volkswagen is like a Porsche. Give it up George. When you get to AirVenture, stop at the HPI tent and look inside the F1 QB. It is definitely not a RV-4. I don't deny the lineage, but the F1 is re-engineered and shares nearly zero parts with any RV.

Last is the engine vs. fuel burn. Many Rocket guys, one in particular say they get better fuel burn than a O320 or O360.

I'm the one and I said better that a O360 at higher MP settings, like above 23 square. I'd be happy to prove it too. All the Rocket guys know it to be true, particularly if you have tuned injectors so you can run LOP effectively.

BTW, if I had to vote between the Harmon and the RV-8 I'd probably go with the RV-8 unless you've built one before. It is not impossible, but it is more difficult to construct a Harmon with both Van's and F1 parts. Visit my friend's web site, www.vincesrocket.com for his story on how he did it. If you're a first time builder, I suspect you'll have a much more pleasurable building experience with the RV-8. Van's sure knows how to do it right.

 

[yarddart]

I have flown both and i bought the 8 .

 

[panhandler1956]

Thanks Randy, I have looked on Vince's site and all that technical stuff is why I have reservations, although I plan to just build a pure HRII with F-1 canopy and possibly F-1 tail feathers, I don't plan to use Mark's firewall and cowling. It would all probably make much more sense with plans and parts/pieces in-hand.

Thanks for all the great replies and keep em' coming!

Has anyone built an HRII that hasn't built a Vans first?
Brent

 

[mark manda]

HR-2 more room inside

The HR-2 is more roomy. Starting with the pedal area. I like the way a Rocket feels and fits-- but nobody sitting next to you to help fold those pesky charts.

I sat in the front seat of the yellow factory 8A at homecoming for twenty mins. and it was okay. 6'2 230#.

I would think you could find someone in Ohio and along with Matronics Rocket- list, stay ahead of the possible fuselage gotchas.

I thought most HR-2 guys are using the pre punched RV-8 emp. as an upgrade.

The Rocket guys I know are all P.O. at fuel prices. They all go straight up and land just so they can take off again.

Much more comeraderie with an RV-8.

Check out my web/homepage(by clicking on my name)-- I have plenty of misc picts of HR-2's and F1's. If you have time to search, they're all over the place.

O.T.-- the other day I saw an awesome F1. I thought it was a Harmon Rocket III (single seat Reno Racer version) but the pilot said it was an F1 built as a single seat. It's all silver and has a custom black three bladed WhirlWind propeller. AWESOME!!!

BTW-- I can't land a 182 anymore. PLUNK.

174MM
RV-7a 125hrs. since Feb. '06

 

[gmcjetpilot]

Humm Humm Humm

In the same way your Volkswagen is like a Porsche. Give it up George. When you get to AirVenture, stop at the HPI tent and look inside the F1 QB. It is definitely not a RV-4. I don't deny the lineage, but the F1 is re-engineered and shares nearly zero parts with any RV.

I'm the one and I said better that a O360 at higher MP settings, like above 23 square. I'd be happy to prove it too. All the Rocket guys know it to be true, particularly if you have tuned injectors so you can run LOP effectively.

I thought my Porsche 993 was a VW, here I am going to the shopping mall.

http://www.metacafe.com/watch/89615/porsche_933_crash/


ha ha ha ha ha. I knew that would get a rise out of you. I have known Mark for years and been hanging out at his tent at airshows for a long time; the F-1 workmanship is fantastic. The ribs fit perfect with no flutes! It is although based on the RV-4, that's all I am saying, geeeeee.

However I reject your VW Porsche premise or anology. It's more like comparing an old 2.2-liter D series to a 3.2-liter Carrera. They are both Porsche's, one just has a bigger engine and is a little longer and wider. Some like the lighter older porsche. Some feel a good pilot does not need all that power........ (I am kidding)

As far as gas milage I Believe YOU! That is why I mentioned it. Touchy, geeeeee. However you DO have the potential to burn 20 gph on takeoff, so that has to average in to the spectacular enroute burn. Not to mention 4 more plugs and more oil. Peace Brother

 

[Tom Martin]

HRII vs 8

I finished my RV4 in 1995 and after a year of flight I found it lacking in size and power. The specifications of the HRII solved all of the things that I felt the RV4 needed. It took me 17 months to build my HRII. At that time there were no websites, I had never seen a HRII in person and the first one I ever saw was mine when it was completed. I found John Harmon and Mark Fredrick to be very helpful. Lest someone say that I rushed through the project that plane won a workmanship award at Oshkosh in 1999. Currently there is a huge base of internet knowledge for you to rely on and a great network of builders and owners.
I have since built another HRII and four F1s. build the plane you want and you will not be dissapointed. It does not have to be much more expensive than an RV8 and done properly those extra dollars will be recovered when the plane is eventually sold.
If you decide to build a HRII I would reccomend the F1 tail rather than the RV4 or RV8 tail. The vertical and horizontal surfaces are better suited to the aircraft and there has been some structural enhancments to the accomadate the higher Vne.

Tom Martin
EVO1 34 hours and climbing

 

[panhandler1956]

Tom,
That's awesome!!!! I appreciate your advice.

Take care,

Brent

 

[f1rocket]

George, you're posting at 2:30 AM???? Don't you ever sleep?

You like to be so factually correct on all your posts, I just thought you would want to be on this one as well! You know, I'm seeing warning signs my friend. You're making up reasons why you need less horsepower, you hang out at the Rocket tent at Oshkosh, etc. Sounds like your slipping over to the Dark side.


Just this weekend, I was cruising with my RV buddies (6 airports in 8 hours, we had a blast). Anyway, on one of the legs, the lead RV-6 (O-360 CS) asked me what my fuel burn was. He was at 8.5. He didn't mention his MP or RPM. I was limping along at 2100 and 18.5 MP buring 8.0. Now that's hardly scientific, but I can usually get below their fuel burn. I like to fly with my RV friends.........it gives me a chance to practice my slow flight.

Another option for building might be a Super RV-8. Kahuna (Mike Stewart) can provide you details on his build. There, you get the benefit of the pre-punched RV kit and the power of the IO-540. It has some drawbacks as well.

 

[Kahuna]

Just this weekend, I was cruising with my RV buddies (6 airports in 8 hours, we had a blast). Anyway, on one of the legs, the lead RV-6 (O-360 CS) asked me what my fuel burn was. He was at 8.5. He didn't mention his MP or RPM. I was limping along at 2100 and 18.5 MP buring 8.0. Now that's hardly scientific, but I can usually get below their fuel burn. I like to fly with my RV friends.........it gives me a chance to practice my slow flight.
.

Randy,
This is exactly what I see all the time. Bout .5gph difference. Course there is everyones calibration. But on avg its .5 .

As for loafing. I love it. It is so pleasant to be at 2100rpm and 18". Quiet, smooth... Its wonderful. I feel like I could fly forever like that. Which I almost can at 7 hours plus reserves.

Im staying out of the rest of the debate.
Covered in other threads.

 

[N395V]

a Super RV-8. Kahuna (Mike Stewart) It has some drawbacks as well.

I really thought long and hard about a 540 powered 8 as it seemed to be the perfect plane but at the time I knew little about RVs Harmons F1s etc.

Never could come up with any problems with the Super 8 just everyone I had heard of was for sale.

Even looked at one and was underwhelmed with the workmanship not the concept.

What are the drawbacks and why are they all up for sale shortly after building?

 

[panhandler1956]

Yeah I considered the Super -8, but honestly it came down to looks. The Rockets are just much more visually appealing to me and since I am spreading the build out the "ease" of the -8 build is temporary but the look of the Rocket is forever - no offense of course, all the RVs are gorgeous airplanes

The S8 seems like a nice airplane though, how is the CG? Even with the battery in the back (way back) it seems like it might be nose heavy, but I'm obviously no expert. I believe the Rockets are a little nose heavy solo too. Any comments from S8 and Rocket drivers on this?

Brent

 

[Low Pass]

After scanning this post, it seems you should broaden your comparison. HR Rockets, F1 Rockets, regular RV-8's and Super -8s. They each have a slightly different story to tell.

If I build again, assuming avgas doesn't go to $8-10/gal, I'll do a Super -8. Having built, owned an -8, I feel very comfortable with the design and integrity. Have nothing against the others, just comfortable with Van's products.

As for the Super -8, I've gone through this in pretty good depth. Couple of us (engineers) believe the conversion of an -8 to a Super -8 would be/is easy. Mods like fastback, O/IO-540, Grove Al gear, shorten the engine mount, stretch the cowling, increase the size of upper longeron and some fuse skins. Minimal derate of the load factor proportionate to the changes in bending moments/lengths with a -540 on the front. Easy mods for essentially Rocket performance. Piece of cake.

As for the resale and looks - the "true" Rockets will probably hold some added value. I think a Rocket (F1 particularly) is a fine looking plane. But the -8 isn't far away. As for price, who knows where they'll end up in 5+ years. All RV's/Rockets may be worth aluminum scrap value if Algore and his followers get their way with use of the internal combustion engine and fuel proces keep climbing.

 

[f1rocket]

Regarding CG, I don't have any problems. Mine came out right where it needed to be with a light weight MT prop out front. I weight about 250 and I can carry a 250 lb passenger with some baggage. I can't comment on the Super 8 CG. I think if you're flexible with the battery location, you can get the CG to be right where it needs to be for your situation.

The only negative I can find about the Super 8 is that if you get it pointed downhill, you will reach red line rather quickly. I slightly disagree with LowPass in that the -8 airframe is not really stressed for ALL the loads you could find yourself in with the IO-540. The Rocket airframe is beefed up, thicker skins, and additional reinforcements in the empennage attachments, empennage skins and trailing edges, etc. That doesn't make the Super 8 unsafe at all, there are just differences and limitations that you need to keep in mind. I fly with two Super 8s and they are great looking and great performing airplanes. I "think" they are slightly slower than my Rocket, but I can't say that for sure. I've never been side-by-side for a comparison with them.

 

[Kahuna]

I fly with two Super 8s and they are great looking and great performing airplanes. I "think" they are slightly slower than my Rocket, but I can't say that for sure. I've never been side-by-side for a comparison with them.

I would say they are since your wing span in a couple feet shorter.
Probably ~7kts Id guess

Best,

 

[Low Pass]

The only negative I can find about the Super 8 is that if you get it pointed downhill, you will reach red line rather quickly. I slightly disagree with LowPass in that the -8 airframe is not really stressed for ALL the loads you could find yourself in with the IO-540. The Rocket airframe is beefed up, thicker skins, and additional reinforcements in the empennage attachments, empennage skins and trailing edges, etc. That doesn't make the Super 8 unsafe at all, there are just differences and limitations that you need to keep in mind. I fly with two Super 8s and they are great looking and great performing airplanes. I "think" they are slightly slower than my Rocket, but I can't say that for sure. I've never been side-by-side for a comparison with them.

I probably got in too much of a hurry above. I agree with you. I wouldn't be too comfortable bolting a -540 on and just going without some other considerations. Personally, I would increase the size of the upper longeron and possibly some of the fwd fuse skins. And even then, I personally would derate my load factor limit.

Also good pt on the red line. The -8 may actually be good for the increased speed beyond the published red line, but I'll let someone else try first!

Super -8 would be good for fast climb and a higher (but most likely red-line limited) cruise spd.

 

[f1rocket]

FYI, this was just posted on the Matronics List:

On another related note, I have a couple of friends with Rockets who I have
flown cross-country with many times. Every time we go somewhere we all fill
up and at our fuel stops we have a friendly contest to see who burned the
least amount of fuel. And every time, without fail, the Rockets beat the
RV's in least fuel used by a gallon or two. Every time the aircraft which
use the most fuel are the carbureted RV's with O-320's and fixed pitch
props. Its funny how counter intuitive that is.

Regards,
Bob Japundza
RV-6 flying, F1 under const.​

 

[Stephen Lindberg]

Just guessing here, but I'll wager the 0-320/fixed pitch guys are running high power settings to keep up with the 0-360 and 0-540 guys. At those higher settings the BSFC goes up pretty quickly and they burn more gas to go the same speed as the bigger engined airplanes. If they slowed down and arrived 5-10 minutes later they would burn way less gas...same trick the 0-540 is doing. Steve

 

[f1rocket]

Well SURE, you can fly SLOWER. Who wants to do that?????

My post was to support my previous statements that I made that at the same speed, my Rocket tends to burn less fuel than my RV flying buddies.

 

[gmcjetpilot]

My Ferrari gets better gas milage than a Toyota Prius at 180 MPH

Well SURE, you can fly SLOWER. Who wants to do that????? My post was to support my previous statements that I made that at the same speed, my Rocket tends to burn less fuel than my RV flying buddies.

First I believe you 100% and it makes sense to me, but.........

"Thou thinkest thee doth protest ye too much"

Lift
Drag
Thrust
Gravity (general theory of relativity, see Einstein)

It's all good. It's a matter of airframe drag, best L/D, prop efficency and engine efficency.

So what is difference? Engine, Prop and Airframe:


ENGINE
I think Randy is contending a 540 is more fuel efficient than a 360 or 360 at the same HP. That may be true. I DON'T know. However we can look at Lycoming data or call them to get a feel for how a 540 at lower RPM or MAP (or a little of both) is more efficient than its smaller bothers working harder. A 540 is just a 360 with two more jugs. However if you can turn slower and make the same HP that improves volumetric efficency and reduces friction losses. OK


PROP
Fact slower turning props are more efficient. By more efficient I don't mean more total thrust I mean more percentage thrust per shaft HP input. So a bigger engine turning slower at higher torque could produce better prop efficency. However the Rocket prop diameter is larger to handle max HP, so there's a little loss in efficency. It may be a wash or a gain? OK


AIRFRAME
Is the airframe of a Rocket way less drag? May be a little with a few feet cut off the wing? OK. Longer gear legs and a little more weight subtract a little bit of the clip wing gain, but as far as weight, it's more about parasitic drag not induced drag. Also the Rocket's fast-back fuselage should be a little less drag than a RV-8 bubble. Wounder how that fast back RV-8 mod is?



Comparing a RV-6A with carb / fixed prop, to a Rocket with fuel injection / constant speed prop for fuel economy does show how efficient the Rocket is, but to be fair............Clearly a Carb and fixed prop looses a little to a fuel injected constant speed prop plane.


APPLES and APPLES

-Tail dragger
-Fuel injected
-Tandem RV-8, RV-4
-Constant speed prop​

Compare like planes, a RV-8 with a IO360 (180HP) and constant speed prop to a Rocket, with typical IO540 constant speed prop.

To say the Rocket is a economy plane of some kind is a tough sell. Don't get mad Randy, I'm on your side. We are all just jealous of your Rocket and have Rocket envy.

It would be nice if some formal cafe foundation fly off between a like RV-8 and Rocket. The old rocket test was removed from their site. That would shut all of us pee shooter RV fliers up. What would be more interesting is the overall average fuel burn say over many typical flying. Your "highway milage" may differ from "city"? The thing about the Rocket is if you are not careful with the throttle and mixture (leaning as much as possible as often as possible) than you have greater potential to waste fuel.

Rocket is fast and efficient, no doubt. It stands to reason it's efficient since it's based on a RV-4 ha ha


PS: The Cafe Foundation Triaviathon Contest winner is a RV-4 (score 2381) by a wide margin to the second place points holder, A HRII (score 1316). I know the RV-4 of Dave Anders was special, but that is the point, compare like equipped planes.

The RV-8A that the Cafe foundation flew (protype with no special prep) had a Triav score just under 1000, compared to the Rockets 1316. So to put it into prespective the Rockets 1316 is excellent. A Cessna C-172 has an approx score from my calculations of 25!!! Where a typical RV is in near 1000!! Rocket 1316!! No wounder we like them.

The score is based on three measure performance parameters, max rate of climb between (2,500-3,500), top speed (@6000 pa) and Min speed (level flight). The Rocket has more ROC than the RV-8, which is a pure HP parameter, more HP the merrier when it comes to climb.

The score is based on this equation:

Score = {28110625 * [ Vmax * ROC ]^2} / {[ 4100625 + (Vso)^4 ] * 10^9}
You could go out and see what kind of score you can get. See Cafe Foundation for how to measure (http://cafefoundation.org/v2/pdf/RV-4.pdf).

 

[Kahuna]

AIRFRAME
Is the airframe of a Rocket way less drag? May be a little with a few feet cut off the wing? OK. Longer gear legs and a little more weight subtract a little bit of the clip wing gain, but as far as weight, it's more about parasitic drag not induced drag. Also the Rocket's fast-back fuselage should be a little less drag than a RV-8 bubble. Wounder how that fast back RV-8 mod is?

8 for 8, I burn less. Like Bob, I travel long distances with lots of RV's. The one set up that gets the closest is a high compression IO-320 c/s. He does real well. But as we get up above 8k', he cant breath enough and we have to power back for him when traveling with other 180hp RV's. Even running hard in the 320, he is very close to me in fuel burn. Bout 1gal in 30 close.

 

[N395V]

Cheap F1 Kit For Sale

 

[panhandler1956]

Milt,
Thanks for the link. That kit actually belongs to a friend of mine. I wish I had 45k today and it would be in my garage vs his. But I will sock away some cash each month and someday I'll be able to take advantage of deals like that - F-1 Tail kit planned for this fall.
He has the engine too, I believe 0 SMOH. It'll make someone a nice airplane!

Regards,

Brent O.

 

[N395V]

Brent,

This fall is not that far away.

Talk to your friend about a price reduction and payment plan.

There is not a huge market for older partially built F1s and he is not likely to get $45K in the near or intermediate future.

He should be happy to jump on the price of an RV 8 kit.

 

[sf3543]

We also occasionally do the gas comparisons on trips and the FP O320s are pretty close but seem to burn more.
BUT...it will take a very long time for them to spend the difference in cost between bigger engines, CS props and governors. Especially since the bigger engine guys usually slow down to fly with them anyway.
I've had both versions and I liked them all!

 

[f1rocket]

We also occasionally do the gas comparisons on trips and the FP O320s are pretty close but seem to burn more.
BUT...it will take a very long time for them to spend the difference in cost between bigger engines, CS props and governors. Especially since the bigger engine guys usually slow down to fly with them anyway.
I've had both versions and I liked them all!

When I built my Rocket, the engine was less than the O360's and the kit was 10K cheaper!!! Not true now though. I don't know if I could afford to build my airplane now if I was just starting. I don't think I spent much more on my Rocket than it would have cost me to build a RV-8, but that's because I got in at the right time.