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  #11  
Old 11-20-2007, 06:45 PM
Bob Axsom Bob Axsom is offline
 
Join Date: Mar 2005
Posts: 5,685
Default It was a good experience

I really felt good when I read John's opening post. I hesitate to say anything because I'm sure I turn people off but I can't help myself. I tend to be a loner but I enjoy the whole cross country race scenario and all the people and planes associated with it. When enroute from turn 1 (Elgin Water Tower) to turn 2 at the Caldwell Airport I heard both exchanges mentioned by Mark and Tom. Believe me when I tell you there was not any idle chatter on the race frequency that I heard - just pilots calling their turns and occassional passes on the race frequency to assure that the monitor personnel or pilot being passed knew that their plane was making the start, turn, finish or pass.

Flat race points like the flying "start line" at Macho Grande (after taking off from Taylor Muni) and turn 2 at the Caldwell Airport are hard to spot from 500 ft AGL at high speed, especially if you have never seen them before and there are trees between you and the runway. When you are streaking in on a turn and your GPS says it should be "right there!" and you can't see it out the windshield the anxiety level gets elevated quickly. When I heard Mark call that he was approaching turn 2 but he couldn't see it, after flying all the way from California to participate in this race, I felt the anxiety. Who ever that guy was that saw him and his position relative to the turn and very clearly and calmly gave him the information, was a real comrade. When Mark acknowledged that he had it in sight and called the turn, well you would have to be made of lead not to feel good about what you just heard - good sportsmanship when it really mattered.

It was a lot of fun but the people there made you feel proud to be a part of it as well. OK, I'll shut up now.

Bob Axsom. Race #71

Last edited by Bob Axsom : 11-22-2007 at 09:17 AM. Reason: Typos as usual
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  #12  
Old 11-20-2007, 08:35 PM
Kevin Horton's Avatar
Kevin Horton Kevin Horton is offline
 
Join Date: Jan 2005
Location: Ottawa, Canada
Posts: 2,357
Default

Quote:
Originally Posted by Tom Martin View Post
As far as modifications I have worked on my cooling air inlets and outlet air to smooth the airflow. This has worked well for me in the cooling department but with the rocket there are not tremendous gains to made in cooling air drag. It is my opinion that it is already a very effiencent system although tweaking will help run the engine cooler.
Tom - In theory, smoothing the air flow in the inlet and outlet shouldn't do much for the drag if that is the only change you make. But, if it improves the cooling, then you can maybe look at reducing the size of the air inlet. That would reduce the amount of air going through the cowling, which would reduce drag. Of course the temperatures would increase too. Nothing comes for free.
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  #13  
Old 11-20-2007, 09:01 PM
Tom Martin Tom Martin is offline
 
Join Date: Jan 2005
Location: Ontario, Canada
Posts: 1,544
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Kevin
That was the interesting part. As I smoothed the inlet area I was able to close off the outlet area. Howver this did not seem to translate into any extra speed. I have tried two variations of cowl flaps and when open they aid in cooling but closing them farther than the neutral point actually causes a speed loss. I have also tried closing off the inlets. This caused an increase in engine temperatures but no corresponding increase in speed. These experiments, which I did not mention before, are another reason which leads me to believe the cowling is quite effiecient in its stock form.
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EVO F1 Rocket 1000 hours,
2010 SARL Rocket 100 race, average speed of 238.6 knots/274.6mph
RV4, RV7, RV10, two HRIIs and five F1 Rockets
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  #14  
Old 11-20-2007, 09:55 PM
Wayne Hadath Wayne Hadath is offline
 
Join Date: Nov 2007
Location: Kitchener Ontario CYKF
Posts: 60
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Hello John
I am the 238 mph square winged F1. The SX300 is running a IO 580 whatever that is. He says 400 HP. I have not had my stock IO 540 with it's twin mags dynoed but I am pretty sure it is no where near 400 hp. I have never in my life raced anything but it sure is fun racing my homebuilt. The cost is nothing. There is not even an entrance fee. A great way to learn is to explore the unknown. By racing these birds it gives those who are interessted a way to discover what effects them. Pretty neat.
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  #15  
Old 11-21-2007, 06:37 AM
RVadmirer RVadmirer is offline
 
Join Date: Dec 2006
Location: Kalifornia
Posts: 466
Default Now you Know ...

"Next, at 242, the Berkut, a retractable gear, glass-backward airplane that I know nothing about."


http://www.berkut13.com/berkut.htm


242 mph on 180 HP
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  #16  
Old 11-21-2007, 07:13 AM
Nuisance's Avatar
Nuisance Nuisance is offline
 
Join Date: Feb 2006
Location: Pagosa Springs, CO
Posts: 130
Default Total Performance

I am going to throw out more numbers...

Ironflight, I have done nothing to the airplane that impacts performance in any other regime. The wings and wingtips are stock (and, Bob can correct me, but I believe he only took off his extended wingtips, which had extra fuel, and I bet either of the stock wingtips would work better than the ones he came up with), the landing speed the same as always. The handling is the same as always. The only difference is that all year, on the average trip, I cruise about 15 kts faster on 10 gph than I did before I started my drag reduction campaign. This of course translates directly into fuel savings.

It is fun to notice every year that the RVs and the Rockets are the only ones who dare fly in to Macho Grande (a very nice grass strip) for the barbecue after the race.

Wayne, you must be right about the SX300...looking at the Reno results, and the last couple of AirVenture Cup races (gee...funny how I look at race results when I want the real performance numbers) he is 10 mph faster than the other SX's. Given the cube law, and the possibility that the others may have tuned their engines, 400 hp may be the number.

I was great to see all my old friends, and to meet all of my new friends.

I would like to throw in a pitch for the AirVenture Cup...it is the best way to fly in to OSH. It involves a lot more pilot stuff than a 100 mile triangle...fuel planning, winds aloft, navigation (yes, ask the airline pilot couple who ended up looking for the finish line in the middle of Lake Winnebago), and the dinner the night before in the Airforce Museum can't be beat.

Try it, you might like it!

John
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  #17  
Old 11-21-2007, 10:20 AM
Bob Axsom Bob Axsom is offline
 
Join Date: Mar 2005
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Quote:
Originally Posted by Nuisance View Post
I am going to throw out more numbers...

... (and, Bob can correct me, but I believe he only took off his extended wingtips, which had extra fuel, and I bet either of the stock wingtips would work better than the ones he came up with)...

Try it, you might like it!

John
John,

I'm sure some theoretician Has conducted a study and published results that suport the excellence of the tip designs used on Van's aircraft. I do not believe that they are optimized for speed. It is a lot of work to produce new wingtips but I know you are not averse to work. I believe if you made up molds, layed up the skin and fabricated new low span tips with no speed compromises your airplane would fly even faster.

There is no question that my airplane is faster because of my tips for racing. Unfortunately I cannot give direct comparrison test results because I had to rush my program for the demands of the end of the racing season. What I mean by that is I had to go from my travel configuration airplane to the short race configuration directly and that involved two changes at the same time.

I have two 9 inch extensions to each wing that contain 8.5 gallons of fuel in each (17 gallons total). On the end of that are two stock 12 inch wide RV-6 wingtips that are rectangular except for the rounded forward corner (no bat wing flare to the trailing edge). Both the 9 inch wide tanks and the 12 inch wide tips were removed.

The plan view (top view) profile of my new tips are a copy of the lower portion of the wing airfoil. Looking from the front, these are shaped from the full airfoil thickness at end of the wing skin at every chord station to a curve tangent to the vertical boundary of the tip plan view. The maximum extension of each new tip is 3 inches from the the end of the wing skins. These caused an immediate jump in speed from struggling to achieve 200 mph to a test and two race proven jumt to a consistent 203 to 204 mph speed.

My actions are greatly affected by race rules. Because the AirVenture Cup organizers started allowing no penalty fuel stops this year I may stick with my short race tips and take advantage of that. It will certainly be my fastest configuration. However, over the winter I have to wrestle with the belief that my tips are faster than the stock tips and do I want to go through the trouble of laying up another set to interface with the outboard of the tip tanks. That would provide the opportunit for an apples to apples comparrison. I have a desire to increase the absolute speed of my plane by developing new wheel fairings and that has priority.

Bob Axsom

Last edited by Bob Axsom : 11-21-2007 at 11:33 AM. Reason: Clarification
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  #18  
Old 11-21-2007, 01:25 PM
grobdriver grobdriver is offline
 
Join Date: Jan 2005
Posts: 17
Default It Was A Good Experience

I think that radio call was from Larry Henney, a Lancair 360 who was two aircraft behind Mark. Our League "Rocket Buster" is he, and was the winner of "SARL Gold", meaning he racked up the most number of points during the race season.

Bob, you mentioned in an email about Jack Morrison - for those who don't know, we had a well known E-Racer come down to race, but he suffered a nosewheel collapse on landing at Taylor. After we raised the aircraft and cranked it down, Jack taxied it to my hangar so we could start repairs - and just in front of the hangar the nosewheel attach failed completely and dropped the aircraft on its nose for a second time!
Needless to say, Jack did not race - rather he spent the weekend repairing his aircraft with the help of any and everyone who could, including local canard builders (Mike Deeter, Velocity), race canard builders (James Redmon and Scott Carter) and others.
Unfortunately when his aircraft was ready to go Monday morning, the weather up North at home base (Chicago) wasn't ready to receive him.
Jack wound up flying home commercially, and will be returning Friday. I will pick him up at ABIA and take him up to Taylor and hopefully see him off.

Here is an email Jack sent that I forwarded to all the racers:

Mike and all who pitched in to make the repair of my AC possible. I cannot
thank you enough for all the assistance and help at a dificult time. Finding
and chasing around for parts as needed was above and beyond and a tribute to the quality of personel at the race event. I have never had such cooperation from so many wonderful people whom most of I did not know. Mike , I especially would like to thank you for the use of your hanger during the repair process. Scott Carter who flew in the nose leg strut attach bracket and supplies from Dallas and spent most of the day Saturday help lay up the necessary glass work.
The AC was ready for flight late Sunday but I was unable to fly home on
Monday because of the weather up north. I will fly down commercial on Friday the 25th and bring the AC back to ARR for completion of repairs. I really felt bad I could not participate in the race but I will be back in the
spring. If anyone ever needs anything up my way, please do not hesitate to
call or email me. Thanks again to everyone, what a fine group of
individuals.

Jack
E Racer 113
Race 29


- Mike
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  #19  
Old 11-22-2007, 12:43 PM
gmcjetpilot's Avatar
gmcjetpilot gmcjetpilot is offline
 
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Posts: 4,285
Default Interesting

Race "100" circuits are never exactly 100 air miles. The Sun and Fun 100 use to be famous for fast times; the course was shorter than 100 miles. Of course pilot performance is a factor as always.

The fastest airplane was the SX300.
Basically a Jet with a piston engine and prop. I understand 105kts approach speed is normal, Awsom

Lancair 360 at 251 mph
A very small tiny airplane, fuselage included, legs stretched out, laying back, but fast, yes.

Next, the F1 EVO (tapered wing) rocket at 249 mph
Yep HP is good but when you hit +250 mph fixed gear starts to be a real liability.

Next a normally aspirated F1 EVO at 243
So all the above EVO HP was worth just 6 mph? Shows HP alone is not key to speed.

Next, at 242, the Berkut
Basically a larger retractable gear VariEze

Next, at 238, a square wing F1 rocket
Next, at 234, a fixed gear Glassair II, with a turbo 360
Next, at 230, two more rockets, an F1 and a Harmon

The Glassair II FG guys have it dialed in an race all the time

Next, my RV8 at 224
Bob Axsom at 203
320 powered RV-4 at 200
360 powered RV-6 at 197

No one should be embarrassed to do about 200 mph or more.

I was asked by several people "where are the RVs?"
May be $4-$5/gal gas?

Comment on Race Inspection
It is very clear people can "cheat" with their engine or what ever. Most race organizers don't check squat. If it was not on the registration you could put a 200HP in and call it 150HP. Some races specify a Cubic inch others a horse power. Is that important? Well if you want an even footing. That's why Reno has those O200 Formula and bi-plane categories. NASCAR has tech inspections to catch little cheater tricks like extra fuel, aero and engine tricks.

With that said, may be some basic tech inspection to catch the obvious should be done. Still even with loose rules and no inspections, its hard to get people. More rules would make it less desirable and enjoyable for many. Basically RUN what ya Brr-rung. Its just fun.

The speeds are interesting but not everything. I see it as a race against yourself and bettering your time each year. May be you have a buddy "fun grudge" you want to beat. We are never going to catch 400HP SX300's. On the other hand SX300 guy can't get into and out of the field for BBQ.

Lets face it, these are FUN runs for no money. There's no limit on mods that I know of. Nitrous Oxide any one? The races I ran, there where VariEze's & LongEze's with super high compression turning 4,000 rpm. Was that fair? Well its all fair in racing if there's no rules to control it.
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Last edited by gmcjetpilot : 11-22-2007 at 01:08 PM.
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  #20  
Old 11-22-2007, 07:05 PM
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logansc logansc is offline
 
Join Date: Feb 2005
Posts: 571
Default

Guys: For anyone in the southeast who would like to get a taste of "just plain fun" racing, check out the Race to Ridgeland we hold each year in May. This next year we'll conduct the race and our fly-in on May 3, 2008. You can check us out at www.racetoridgeland.com. Our race is handicapped to each aircraft's manufacturers published sea level top speed (last year a Cessna 172 won!). This year, to make it more fun, we are adding a couple of additional trophies, one for fastest Experimental and one for fastest Production aircraft. No classes, few rules, tons of fun with food, displays, a spot landing contest, etc. We're at 3J1, Ridgeland, SC.

See you there!

Lee...
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