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RV-8 vs Harmon Rocket

Stroh21

Well Known Member
Hello VAF!

I'm ready to pull the trigger on starting an airplane build, now I need to decide which one. I've narrowed it down between a RV-8 and a Harmon Rocket. My question is, how much faster is a Rocket vs the RV-8. I know the RV-8 usually cruises between 180-190 True Air Speed. For the Rocket owners out there, how much faster is it? Trying to decide if loosing the extra baggage space is worth the speed.

Thank you for your time!

Astro
 
Hey Mike,

I'm not really worried about the build time. I already own an RV-8A (and love it!). I'm starting this as a hobby and to achieve a bucket list item.

I'm getting close to retiring from the Air Force and the wife has approved me to start building :).

Astro
 
When you say "more room" are you talking personal space or baggage space?

If there are any Rocket's near Portales, New Mexico, I'm hosting a fly-in September 22nd if anyone wants to drop in and show it off!
 
There was a Harmon Rocket II at the land of enchantment fly-in this last weekend. Sexy bird.

From what I gather the Harmon Rocket is a more "Raw" build, largely from plans. The F1 Rocket seems to have more kittable parts you can buy, and you supplement the rest with RV parts.

There is some more info on differences in the archives and a recent post in the Rocket sub-forum. It sounds like the F1 rocket is usually a bit faster(something like 3kts). This depends on which wing/tail you end up building, but the original F1 EVO wings are no longer available. They were teasing that a new EVO wing is being designed but no idea when it will be available or what capability it would provide.

There are pictures of Rockets flying at 230-240mph TAS at around 11GPH on this forum.

Another option is the F4 Raider which is a F1 Rocket design and ascetics flying a 4 cylinder instead of a 6.
 
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I haven't flown either, but my impression of sitting in the -8 and an HRII on the ground is that there is more room for the pilot in an HRII (I expect the F-1 is similar). This seems counterintuitive as the Rocket is based off the -4 which is smaller to start with, but that's the impression I got sitting in them. In particular what I noticed was the wider stance for your feet in the Rocket... I found the -8 to feel constrictive with the gear towers forcing your feet together. I seem to recall from rides in both that the opposite was true in the back seat, the -8 being roomier for the passenger than the Rocket.
 
Bucket list

Well, get a ride in one 1st - then decide.

If you want to take the high road, there are F1's for sale every now and again, and once in a while an Evo pops up (~40 were produced). Vince is hard at work getting the F1 back into production, and I think all but the wing are available?

The luggage is aft, and is huge. Personal room is similar, but the rudder pedals on the Rocket are a bit more ergonomic, and the panel is not so close to your face.

The Evo wing was a heavy-duty design, but it sure does perform. I think Vince & Co are gonna have a similar wing with similar numbers, but easier to produce and lighter.

I can say that my ship will show 200KTAS on 11GPH 22"/2200 at 8500' on a warm day, and 214KTAS on the same fuel at 17500'. Fastest lap at Reno with that plane was 264MPH.

If you want to putter around, it will also show 125KIAS on 5.5 GPH 1800/16".

But my signature says it all...
 
Mike S,

I thought about the Super 8, but it seems like the Rocket/F-1 is faster? If I'm going to take the time to build one, I want it to be significantly faster than the 8A I have now.

Mark (F1Boss),

I just looked up Taylor, TX. I may need to fly down from Clovis, NM and visit! It is only about a 2.5 hour flight. :)
 
I have built and flown both a Harmon Rocket II and a RV-8A. The Harmon Rocket was a wonderful flying machine, honest handling characteristics, relatively easy to land, good builders support from John, etc. With a worn out, stock C4B5- IO-540 it would cruise at 200KTS all day long. My RV-8A with a mildly massaged new IO-360, cruises in the 175-180 kt range under similar circumstances. The Rocket does have more leg room in the back seat. Why did I sell the rocket and build a -8A? Several reasons, first was that at 130 TT piloting, I found landing with two persons a little nerve wracking for my skill level, one person- piece of cake. Second, and more importantly, my Rockets used engine was ****, and I was going to have to spend big bucks for a rebuild in order to feel comfortable. Third issue was hull insurance. The Rocket was three times my -8A insurance. Forth reason was lack of headroom, my head would hit the canopy in bumpy conditions (I'm six feet tall with a long trunk.) And finally, the RV-8A has double wall floor construction from the wing spar forward to the firewall. The Rocket has one skin between one's feet and the ground- so to speak. So for all those reasons I decided to build a tricycle geared aircraft, so easy to land, and was able to include modern avionics and auto pilot (greatest thing since sliced bread).
 
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...For the Rocket owners out there, how much faster is it? Trying to decide if loosing the extra baggage space is worth the speed...

I have both in my hangar, and "I" can hardly bring myself to fly the -8 when the Rocket is airworthy... The little guy just sits in the corner.

That said, you need to sit in a Rocket to see if the cockpit works for you. I strongly prefer the comfort of the Rocket to the -8, but that doesn't mean everyone will.

The baggage space issue is manageable. I have done plenty of maxed out cross country flying in both and I really appreciate the loading options of the -8, but if you are building, the rear space in the Rocket can be cavernous. As for CG, with my wife in back I can still pack over 100 pounds in there and remain in CG and GW. That's a lot of stuff!

As for performance, you only have to read the PIREPS. There's just no comparison. 35-40 KTAS faster at the same or better MPG, double the rate of climb.
 
Yeah, I need to find one to sit in. I'm 6'2", but pretty comfortable in tight spaces.

Seems like the F-1 has their kits available again. I sent them a message to get more details.
 
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What could possibly go wrong??

Mike S,

I thought about the Super 8, but it seems like the Rocket/F-1 is faster? If I'm going to take the time to build one, I want it to be significantly faster than the 8A I have now.

Mark (F1Boss),

I just looked up Taylor, TX. I may need to fly down from Clovis, NM and visit! It is only about a 2.5 hour flight. :)

I?m headed to Reno next week (some sort of speed event there - I get to be Ramp Boss for the Sport Class) and I?ll be stopping for fuel in Holbrook for fuel next Thursday, 6 Sept. You are welcome to meet me there if that is convenient. The plane will be packed for travel, so I can?t give you a ride - but you are welcome to ?try it on?.

F1boss at Gee mail if you want to discuss off list.
 
Thank you F1Boss! Thursday's are normally very busy for me at work. Maybe I'll be able to catch you on the way back! Worst case, we'll fly down to your home airport in a few weeks and spend the weekend in San Antonio.
 
Rocket vs RV-8

If you can take Mark up on his offer, do so. You won't regret it.

When I decided to take the plunge in 1997, I was deciding on the 4, 8, and the Rocket, and sat in all three. Had a friend who built a 4, and when I closed the canopy, I bumped my head. I went up to Vans and sat in the 1st built 8. A lot more room, but my shoulders rubbed on the side rails. Went down and visited John in Bakersfield and sat in his Rocket. That sold me, even more after he took me for a ride. The Rocket is 4" wider in the front seat, and 4 more inches of leg room in the back seat than a 4. The big decision is if you want the sliding canopy, or tip over. Personally mine has the tip over, which I find so much easier to get in and out of, but there is advantages of the slider. You have to try both and see what you prefer.

I bought his plans, ordered my tail kit and 14 years later I had a flying original HR2. For flying heavies for many years, it took a bit sitting sooooooo low to the ground, but you will get use to it.

I don't fly it as much as I like do to my work schedule, but I never regretted my decision.

It won't make a difference if you go with the HR2 or th F-1, both Mark and John will be very helpful in your build.

Mark, see you in 10 days in Reno, fly safe.

Brian
 
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SARL race speeds

Rockets are clearly faster than RV-8s, but its difficult to get a realistic idea how much faster based solely on anecdotal reports. About 7 years ago I used race data compiled by Bob Axsom over a period of several years of SARL racing to compare speeds of different aircraft types. These data are based on groundspeed only (generally over a closed course), but wind and other conditions tend to average out if enough races are included.

The result I got was that Rockets on average were about 10% faster than RV-8s at race speed, presumably at 50% greater average fuel flow (wide open throttle, 6 cylinders vs. 4). 10% is huge in racing however. The difference may be even greater at normal cruise since speed varies with the cube of power?

More impressive to me was the climb rate difference. I recall getting dramatically out-climbed one occasion by two passing Rockets.
 
At 6'2" and on the large side, there is no comparison... the Rocket is like a living room compared to the RV-8.

Let's face it. You know what you want...

Here's are pictures of the one for sale in Langley:
C-GCPC.jpg


IMG_4010_1.JPG


V
 
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Rockets are clearly faster than RV-8s, but its difficult to get a realistic idea how much faster based solely on anecdotal reports...

...The result I got was that Rockets on average were about 10% faster than RV-8s at race speed, presumably at 50% greater average fuel flow (wide open throttle, 6 cylinders vs. 4). 10% is huge in racing however. The difference may be even greater at normal cruise since speed varies with the cube of power?

More impressive to me was the climb rate difference. I recall getting dramatically out-climbed one occasion by two passing Rockets.

Data from my stable:

RV-8 165 KTAS @ 8.5 GPH (19.4 MPG)
Rocket 202 KTAS @ 11 GPH (18.3 MPG)

I have hundreds of hours of cross country time in both, typically loaded to the gills with PAX and bags.

Between my two ships, a little more than 1 GPH buys you 22% more cruise speed when I pick the Rocket. This is the main reason the -8 sits in the corner most of the time.

Though I dont go flat out very often, I have done some limited testing and the results are as follows:

Rv-8 178KTAS @ 17.5 GPH (10 MPG)
Rocket 220 KTAS @ 25 GPH (8.8 MPG)

Once again, the Rocket outpaces my -8 with a 26% increase in speed for the cost of a bit more than 1 MPG.

Before someone jumps in with their RV-8 numbers, understand that both of my airplanes are pretty dirty, probably solidly in the "typical" realm. Yes, many -8's can do better, but so can many Rockets. When flying again with the SDS EFI, cooling mods and aero cleanup I expect my Rocket to be consideably better than the above numbers.
 
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Thank you for the numbers analysis. I agree, getting an "accurate" speed assessment is the most difficult part when comparing aircraft.

I know this next question is opening a can of worms, but is there a appreciable speed difference between the F1 and the H2 rockets? Also, I know the F1 is a kit on it's own, but is the $10k difference worth the extra cost?
 
Speed between the F-1 and HRII is based primarily on attention to the build. Again drawing from the "real world", the group of 6 Rockets that I run with (3 are F-1's and 3 are HRII's), 1 particular F-1 is the fastest, followed by a HRII a close second. Among the rest of us there's no practical difference. Some day if we can ever get all 6 of us airborne together we will do a balls out race to see who has bragging rights.
 
Data from my stable:

RV-8 165 KTAS @ 8.5 GPH (19.4 MPG)
Rocket 202 KTAS @ 11 GPH (18.3 MPG)

Though I dont go flat out very often, I have done some limited testing and the results are as follows:

Rv-8 178KTAS @ 17.5 GPH (10 MPG)
Rocket 220 KTAS @ 25 GPH (8.8 MPG)

Interesting comparison, thanks. I'm curious, what are the altitudes for these numbers?

I don't have anything to compare to the Rocket, but my RV-8 does more like 188 KTAS down low and wide open on a warm day, on a couple of GPH less (180 hp, carb, CS). I know others that beat me regularly in races. Anecdotal report!
 
At RV speeds a rocket will burn less fuel. Jim Winings and I used to fly a lot of cross country trips together. When we would stop and fill up he'd always be a few tenths of a gallon less than I would in my RV6.
 
No comparison...

Hello VAF!

I'm ready to pull the trigger on starting an airplane build, now I need to decide which one. I've narrowed it down between a RV-8 and a Harmon Rocket. My question is, how much faster is a Rocket vs the RV-8. I know the RV-8 usually cruises between 180-190 True Air Speed. For the Rocket owners out there, how much faster is it? Trying to decide if loosing the extra baggage space is worth the speed.

Thank you for your time!

Astro

Astro,
I owned my early model HR2 for 4 wonderful, fun, adventurous albeit expensive years. Having flown just about every iteration of the RV8 except the Six banger, there is no comparison.
The HR2 is far superior in takeoff, climb and cruise and personally I like it's handling and solid feel in turbulence. The shorter wing with more ribs is higher wing loading and being an RV4 wing with it's laminated spar (vs -8 solid extrusion) is arguably stronger.
Cockpit room and rear passenger room are also excellent as well as my extended baggage matched any baggage capability the 8 offers..

Downsides: Building a hybrid kit or melding add on parts to a existing kit. However comma, there is lots of information, parts drawings and expertise available right here. Flyboy accessories as mentioned above offers the F-4 raider mod and F-1 parts now.
Other downside is cost. My annual fuel bill & insurance cost was exactly twice my RV4's, for what it's worth.

Speed? I flight planned 190KTAS at 10GPH (65%) at 10,500' with 50 gallons aboard gave me nearly 1000NM range. Mine wasn't the fastest HR2 but I saw 230KIAS once flat out at 29"/2800RPM. (LyCon IO-540C4B5, Gami injectors, 10:1 Comp, E.I.)
Additionally, I flew it from my 1500' soft home turf strip in FL and took it into many gravel/dirt strips in ID and CO.

Any way you slice it the FB-4, Raider/Harmon Rocket or F-1 are wonderful Sport Planes and my HR2 was the closest thing to a personal F-16 I can think of. Trust me...:)
You won't be disappointed.


V/R
Smokey
 
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