German Speedcup 2013
07-23-2013, 11:32 AM
#76
RE: German Speedcup 2013
That is great stuff, HP.
If I could do the RC hobby over again I would have found a way to get more involved with racing......but truthfully I don't think I've ever had enough discipline to put in the behind the scenes prep work to have ever been good at it.
Strom was "born into it" and Tony Huber is one of the most resourceful and capable guys I've ever met.
Tony's advice to me for my first heat was, "Don't forget to breathe".
About Strom....... He was mainly a so-so combat pilot, [nothing extraordinary]...but.......
he has a gigantic son who could just really "take it or leave it" as far as this hobby is concerned. Somehow Tom got this young man interested enough to at least grab a handle and enter some combat contests. He became an over night sucess and won several contests including the big one.... The Bladder Grabber, where the winner must prevail over 50 to 100 entrants depending on the turn out. and against guys who have been flying for 10-20-40 years.
To make matters worse......
Tony Huber and his brother got his teenage niece interested in combat and SHE became an overnight terror.
She also won a Bladder Grabber.
I think I decided to "hang them up" after that contest.
If I could do the RC hobby over again I would have found a way to get more involved with racing......but truthfully I don't think I've ever had enough discipline to put in the behind the scenes prep work to have ever been good at it.
Strom was "born into it" and Tony Huber is one of the most resourceful and capable guys I've ever met.
Tony's advice to me for my first heat was, "Don't forget to breathe".
About Strom....... He was mainly a so-so combat pilot, [nothing extraordinary]...but.......
he has a gigantic son who could just really "take it or leave it" as far as this hobby is concerned. Somehow Tom got this young man interested enough to at least grab a handle and enter some combat contests. He became an over night sucess and won several contests including the big one.... The Bladder Grabber, where the winner must prevail over 50 to 100 entrants depending on the turn out. and against guys who have been flying for 10-20-40 years.
To make matters worse......
Tony Huber and his brother got his teenage niece interested in combat and SHE became an overnight terror.
She also won a Bladder Grabber.
I think I decided to "hang them up" after that contest.
07-30-2013, 11:24 AM
#77
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RE: German Speedcup 2013
ORIGINAL: HighPlains
If gravity is not the big issue, then I suggest you guys prove this by only allowing a flat turn into the speed trap next year. I would expect at least a 30 mph (50 km/h) drop in speeds, perhaps more.
Wrong, not within 200m. The speed drops that´s correct maybe 20mph but no more. Not within 200m.
We have to remember that for any correct FAI World Record and German Mastership flight the planes have to stay between 35 and 5 m of altitude already 100 meters before the 200 m speed trap (see sketch below).
In fact parallelly carried out speed measurements using the Stalker Pro radar gun within the 100 m sector right in front of the 200 m speed trap showed up to 50 mph more speed than the final speed trap speed result.
So if a plane achieves an averaged trapped speed of let's say 240 mph then the entry speed during the first 100 meters in front of the 200 m speed trap was about 290 mph. At the end of the 200 m speed trap however the actual speed recorded by the Stalker gun was only about 190 mph in this example.
Clearly this example shows the importance of the FAI type measuring rules, i.e. to measure time over distance being much more objective than the isolated punctual recording by a radar gun or by Doppler audio shift (for that all Dynamic Soaring speed results cannot be evaluated objectively – sad but true).
In fact parallelly carried out speed measurements using the Stalker Pro radar gun within the 100 m sector right in front of the 200 m speed trap showed up to 50 mph more speed than the final speed trap speed result.
So if a plane achieves an averaged trapped speed of let's say 240 mph then the entry speed during the first 100 meters in front of the 200 m speed trap was about 290 mph. At the end of the 200 m speed trap however the actual speed recorded by the Stalker gun was only about 190 mph in this example.
Clearly this example shows the importance of the FAI type measuring rules, i.e. to measure time over distance being much more objective than the isolated punctual recording by a radar gun or by Doppler audio shift (for that all Dynamic Soaring speed results cannot be evaluated objectively – sad but true).
07-31-2013, 08:39 AM
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RE: German Speedcup 2013
Vic, I am not shocked by your not hearing from them in the least, I have sent several emails myself inquiring about a copy of the F3s rules, the FAI seems to pretty much ignore us here in the states.
Have you heard from Christian Erdt regarding the measurement system? If not perhaps you could PM Sascha or Michael and see if they could get in touch with him for you. It might just be that he is busy or on holiday, they seem to have a much better deal as far as vacation time in Europe. I know a couple of guys I worked with in the UK had a much better deal than I had, and we both worked for the same corporate entity.
HighPlains,
Very interesting quotes that you posted regarding the speed changes that they observed. It would be very interesting to have one of those planes equipped with a airspeed recorder like Eagle Tree produces and see just how fast the plane was flying during the entire flight start to finish. Reading what ILJ was saying it sounds like as they exit the course they are only doing about 65% of the speed that they entered it at.
Have you heard from Christian Erdt regarding the measurement system? If not perhaps you could PM Sascha or Michael and see if they could get in touch with him for you. It might just be that he is busy or on holiday, they seem to have a much better deal as far as vacation time in Europe. I know a couple of guys I worked with in the UK had a much better deal than I had, and we both worked for the same corporate entity.
HighPlains,
Very interesting quotes that you posted regarding the speed changes that they observed. It would be very interesting to have one of those planes equipped with a airspeed recorder like Eagle Tree produces and see just how fast the plane was flying during the entire flight start to finish. Reading what ILJ was saying it sounds like as they exit the course they are only doing about 65% of the speed that they entered it at.
07-31-2013, 09:18 AM
#80
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RE: German Speedcup 2013
To be fair, that was at the 2008 Speedcup, perhaps there have been significant improvements in the laws of physics.
http://www.rcuniverse.com/forum/m_8000493/tm.htm
What has struck me most in the past is that the 6.6 class is almost as fast as the 10 and 15 class. Clearly better airframes plus the advantage of more RPM over the larger engines.
http://www.rcuniverse.com/forum/m_8000493/tm.htm
What has struck me most in the past is that the 6.6 class is almost as fast as the 10 and 15 class. Clearly better airframes plus the advantage of more RPM over the larger engines.
07-31-2013, 12:33 PM
#81
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RE: German Speedcup 2013
The 10 and 15 cc classes were within a tenth of a mph of each other the 15cc was only a fraction faster. What really stuck me was what they are able to get out of the electrics, there seems to be a clear advantage there, upwards of 30 mph. As a guess I would imagine that they set the upper power limit to match the IC engines.
07-31-2013, 12:53 PM
#83
My Feedback: (202)
RE: German Speedcup 2013
There is a point of diminishing returns when it comes to speed within a certain engine class. At this point is where power is replaced with research ( aerodynamics and airframe study ) and money! Look at the Unlimited Class of air racing. Power is an essential but aerodynamics and construction are equally, if not more important. A "stock" P-51 airframe will only fly so fast no matter what you power it with. Power comes in many forms. You would be amazed at the power generated by 300 lbs of water ballast in a competition sailplane. I can see the advantages of having a powered configuration of a sailplane type airframe as submitted by the top speed dogs in the Germany Speed event. I am not a sailplane guy. I love props and fuel but the "Hotliner" airframe concept is becoming hard to beat.
07-31-2013, 01:57 PM
#84
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RE: German Speedcup 2013
F3D posted the following on the first page:
If I'm not mistaken, in past years the wing loadings in all classes was limited to 75 Grams / dm2 which is about 24.578 oz/ft^2
But now they have taken the wing loading up to 32.77 oz/ft^2 for wet power
This would allow the same airplane to gain more speed in a dive than the lighter loading.
Gravity games, oops, I mean Gravity gains
the max wing load is by the electric driven models 75Gramm/ dm2 = FAI legal, with combustion engine it is 100Gramm/dm2.
Gravity is not a big issue, it is power ( good set up) and a good design of the model.
Best regards Michael
Gravity is not a big issue, it is power ( good set up) and a good design of the model.
Best regards Michael
But now they have taken the wing loading up to 32.77 oz/ft^2 for wet power
This would allow the same airplane to gain more speed in a dive than the lighter loading.
Gravity games, oops, I mean Gravity gains
07-31-2013, 06:23 PM
#85
RE: German Speedcup 2013
Let's not lose sight of the fact that the object is to PARTICIPATE and have FUN in this sport with a set of rules that is agreeable to [and also within reach of] the average guy who wants to dedicate his free time to pursuing.
Has anyone here spent a large proportion of their annual "take home income" and energy producing carbon fiber props that might [or might not] end up becoming slightly better than the props already in production..?
The best way to demonstrate "how silly" this FAI event is..is to show up un-announced and establish a world record speed run on your first attempts right there on the grass.
Has anyone here spent a large proportion of their annual "take home income" and energy producing carbon fiber props that might [or might not] end up becoming slightly better than the props already in production..?
The best way to demonstrate "how silly" this FAI event is..is to show up un-announced and establish a world record speed run on your first attempts right there on the grass.
07-31-2013, 07:44 PM
#87
My Feedback: (1)
RE: German Speedcup 2013
Way back in 2005 there was a discussion of just how fast the old Formula One aircraft were, both on the 2 1/2 mile racing course and when flown wide open without having to turn as often.
http://www.rcuniverse.com/forum/m_33..._1/key_/tm.htm
In essence, while on the course 175 mph was about the best was observed with radar on a race course. The defining condition of racing is a turn after two seconds on the straight-a-way, and about a 30 G turn, so the wing is generating 150 lbs. of lift during the turns,.
One poster was testing a F1 with long approaches to the speed trap more or less level with a long approach. The fuel was mild 30% nitro fuel and was propped with a bit higher pitch than used on a race course. Their best speed was an interesting 207 mph. I was not too surprised to see 200 under those conditions, because of some flights after practice sessions with my own F1's back in the day. I just never had a radar available at those flying sessions to quantify my results.
Why my interest in these numbers? Well a 5 lb.+ F1 was a pretty big model compared to an all out speed design. It's fuselage was 7" high and 3 1/2" wide, with landing gear and a big wing that was 1" thick. It also had two fairly large cheek cowls right behind the prop. Yet it could go easily into the 175 to 200 mph regime with little effort. This without a tuned pipe either, just NITRO.
Now if you downsize the airplane, getting rid of the landing gear, extra cheek cowl, excess fuselage size, and reduce the wing area you should end up with about 60% of the drag of a F1 design. According to a graph in my copy of Bruce Carmichael's "Personal Aircraft Drag Reduction", 60% of the original drag should allow the speed of an airplane to increase by 20%. 120% of 175 would be 210 mph, while 120% of 200 is off the charts. Getting that much reduction in drag might be difficult, but 20% less drag would be easy.
Just removing the landing gear is worth about 7 to 10% of the total aircraft drag. Reduction of the fuselage size should drop about 15% from the original drag, while wing/tail size reduction would account for another 10%. So maybe getting down to 60% of the original drag might be almost possible.
If you had 80% of the drag of a F1 design, you should be able to achieve a 108% of the F1 speed, so you should be in the 190 to 220 mph range with the same power. Since the tight turns every two seconds are gone, the trap speed should be in the higher end of the calculated ranges.
http://www.rcuniverse.com/forum/m_33..._1/key_/tm.htm
In essence, while on the course 175 mph was about the best was observed with radar on a race course. The defining condition of racing is a turn after two seconds on the straight-a-way, and about a 30 G turn, so the wing is generating 150 lbs. of lift during the turns,.
One poster was testing a F1 with long approaches to the speed trap more or less level with a long approach. The fuel was mild 30% nitro fuel and was propped with a bit higher pitch than used on a race course. Their best speed was an interesting 207 mph. I was not too surprised to see 200 under those conditions, because of some flights after practice sessions with my own F1's back in the day. I just never had a radar available at those flying sessions to quantify my results.
Why my interest in these numbers? Well a 5 lb.+ F1 was a pretty big model compared to an all out speed design. It's fuselage was 7" high and 3 1/2" wide, with landing gear and a big wing that was 1" thick. It also had two fairly large cheek cowls right behind the prop. Yet it could go easily into the 175 to 200 mph regime with little effort. This without a tuned pipe either, just NITRO.
Now if you downsize the airplane, getting rid of the landing gear, extra cheek cowl, excess fuselage size, and reduce the wing area you should end up with about 60% of the drag of a F1 design. According to a graph in my copy of Bruce Carmichael's "Personal Aircraft Drag Reduction", 60% of the original drag should allow the speed of an airplane to increase by 20%. 120% of 175 would be 210 mph, while 120% of 200 is off the charts. Getting that much reduction in drag might be difficult, but 20% less drag would be easy.
Just removing the landing gear is worth about 7 to 10% of the total aircraft drag. Reduction of the fuselage size should drop about 15% from the original drag, while wing/tail size reduction would account for another 10%. So maybe getting down to 60% of the original drag might be almost possible.
If you had 80% of the drag of a F1 design, you should be able to achieve a 108% of the F1 speed, so you should be in the 190 to 220 mph range with the same power. Since the tight turns every two seconds are gone, the trap speed should be in the higher end of the calculated ranges.
07-31-2013, 08:22 PM
#88
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RE: German Speedcup 2013
If it's not F1 you can go even thinner on the wings couldn't you, and you could make them progressively thinner from the root to the tips?
Trying to get the weight down to 3-4 lbs AUW should be beneficial as well wouldn't it?
I would think that you may be able to do a fuselage that is 2.5 inches high and 3.5 inches wide with little or no problem. How would that compare to the 7 X 3.5 fuselage as far as drag reduction do you think?
I guess this would fall under the heading of an animal class F1.
Trying to get the weight down to 3-4 lbs AUW should be beneficial as well wouldn't it?
I would think that you may be able to do a fuselage that is 2.5 inches high and 3.5 inches wide with little or no problem. How would that compare to the 7 X 3.5 fuselage as far as drag reduction do you think?
I guess this would fall under the heading of an animal class F1.
08-01-2013, 04:33 PM
#89
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RE: German Speedcup 2013
HighPlains,
You are just throwing numbers at it basically...
Trust me: the guys with the 250mph planes are throwing everything they have at it. If it were that easy, everyone would do it. But it isn't.
I was at the WC F3D last week rootin' for ¨Team Belgium...the VooDoo's are doing 230 mph on the straights...but that last 20mph is a hard nut to crack.
Electrics may be the way of the future, but there is something fascinating about getting as much power out of a .61 as one can...it is an art, plain and simple, and I love it!
You are just throwing numbers at it basically...
Trust me: the guys with the 250mph planes are throwing everything they have at it. If it were that easy, everyone would do it. But it isn't.
I was at the WC F3D last week rootin' for ¨Team Belgium...the VooDoo's are doing 230 mph on the straights...but that last 20mph is a hard nut to crack.
Electrics may be the way of the future, but there is something fascinating about getting as much power out of a .61 as one can...it is an art, plain and simple, and I love it!
08-01-2013, 04:34 PM
#90
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RE: German Speedcup 2013
ORIGINAL: combatpigg
Let's not lose sight of the fact that the object is to PARTICIPATE and have FUN in this sport with a set of rules that is agreeable to [and also within reach of] the average guy who wants to dedicate his free time to pursuing.
Has anyone here spent a large proportion of their annual ''take home income'' and energy producing carbon fiber props that might [or might not] end up becoming slightly better than the props already in production..?
The best way to demonstrate ''how silly'' this FAI event is..is to show up un-announced and establish a world record speed run on your first attempts right there on the grass.
Let's not lose sight of the fact that the object is to PARTICIPATE and have FUN in this sport with a set of rules that is agreeable to [and also within reach of] the average guy who wants to dedicate his free time to pursuing.
Has anyone here spent a large proportion of their annual ''take home income'' and energy producing carbon fiber props that might [or might not] end up becoming slightly better than the props already in production..?
The best way to demonstrate ''how silly'' this FAI event is..is to show up un-announced and establish a world record speed run on your first attempts right there on the grass.
08-01-2013, 07:31 PM
#92
My Feedback: (1)
RE: German Speedcup 2013
Rudeboy,
I am looking at the available data, doing a bit of analysis, and applying known aerodynamic equations. It's what engineers have done for over the past century. Other than the electric airplanes, none of the IC German designs are 250 mph airplanes. Not even close without the big dive, which gives speeds they cannot sustain. Have them fly level for a km and then I will be impressed with their trap speed. I think that it is quite possible for a .40 sized model to reach about 215 +/- 5 mph using 20 year old F1 motors without diving. If I was interested in airspeeds from climbing and diving, I would skip having an engine altogether and go dynamic soaring and see if 4-500 mph is really possible.
I am looking at the available data, doing a bit of analysis, and applying known aerodynamic equations. It's what engineers have done for over the past century. Other than the electric airplanes, none of the IC German designs are 250 mph airplanes. Not even close without the big dive, which gives speeds they cannot sustain. Have them fly level for a km and then I will be impressed with their trap speed. I think that it is quite possible for a .40 sized model to reach about 215 +/- 5 mph using 20 year old F1 motors without diving. If I was interested in airspeeds from climbing and diving, I would skip having an engine altogether and go dynamic soaring and see if 4-500 mph is really possible.
08-06-2013, 11:09 PM
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F3D posted the following on the first page:
If I'm not mistaken, in past years the wing loadings in all classes was limited to 75 Grams / dm2 which is about 24.578 oz/ft^2
But now they have taken the wing loading up to 32.77 oz/ft^2 for wet power
This would allow the same airplane to gain more speed in a dive than the lighter loading.
Gravity games, oops, I mean Gravity gains
If I'm not mistaken, in past years the wing loadings in all classes was limited to 75 Grams / dm2 which is about 24.578 oz/ft^2
But now they have taken the wing loading up to 32.77 oz/ft^2 for wet power
This would allow the same airplane to gain more speed in a dive than the lighter loading.
Gravity games, oops, I mean Gravity gains
FAI rules , IC and electric are 75gr.
so the world record airplanes have 75gr!
Not all pilot fly with big diving! for example: Christian Erdt fly a "dragster" (electric) Setup! without diving 422kmh (~260mph)
with a 3 blade folding prop 12x25"
rgds
Sascha
