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Could anyone who has considerable acro experinence give me an answer to 2 questions? And any informed opinion is fine.
1. Is there a max wind limit for an acro contest, with the usual planes, Pitts , Yaks, Extras, Decathlons, etc.?
2 If someone is doing a half cuban 8 in a warbird, say P-51, or T-6, what g force do you think they reach?
Thanks
1) Per IAC rules: "Flight will not be conducted if the wind speed exceeds 20 knots, except at the discretion ofthe Contest Jury."
2) Are you asking about a competition quality figure, or an airshow cuban? Of all the warbird (airshow) acro I've seen, I'd guess they don't typically pull more than around 4G for any given figure. It's completely up to the pilot what kind of G you want to put on the airplane. I've done all the basic figures in a T-6, and they were all right around 4G. But the looping portions were not actually round. Given a particular aircraft's airspeed/power combination, you'll need a certain amount of G to make a looping figure round - as in the 5/8 loop in a cuban. Most warbirds to do not actually do round loops, so a "display" loop or cuban could be done at lower G than an actual round competition cuban, which may require more airspeed and a harder pull, depending on the airplane. You planning on bringing a T-6 to a contest? :-) I was once at a contest that had a T-28 participating. Now that was entertaining.
The answer to the wind question in practice is that the contest jury polls the competors and decides to fly unless there is a real safety issue. I have seen something like 40kts in the box (took home 1st place Intermediate that time). We go to contests to fly, not to sit, so we fly. I have seen contest flying put on hold due the wind across the only runway. Everyone agreed that it was good policy to not get the less experienced pilots in over their head when taking off and landing. So we sat for a couple of hours. But if the wind handicaps everyong equally, the vote is to fly.
As for the warbird guys, the ones that I have spoken to generally fly to +4G and no negative. Warbird acro is generally smooth and flowing in deference to the age and value of the airframes.
Hope this helps,
Wes
N78PS
Most any maneuver can be done at 4G or less.
A T-28 doing aerobatics? Now that would be a weird sight and probably a pretty interesting noise as well. LOL
Two or three years ago, at the Warrenton, VA East Coast Aerobatic Contest, a local T-28 owner entered and flew Primary. He started higher than the top of the box so that he has plently of room for the spin. He flew safely, I think that he scored OK, and the gallery was greatly entertained. Have not seen that since though.
Competition aerobatics has several dimensions of performance that you must manage. One is that the box is 3500' wide, 3500' deep, and 3500' high. I will hazard a guess that in a large, heavy, machine like a T-28 the box seems really really small and wrestling it through the figures in that space is really really hard work. Its an arena for ballerinas, not WWE wrestlers.
Wes
N78PS
Yeah, that same T-28 flew Sportsman at Warrenton a couple years ago just for fun. It could do everything OK except for the hammerhead. It seemed to have a lot of torque and not a lot of rudder. It got near the top, and he tried to pivot it, but it just torqued off about 90 degrees before flopping back down, and he continued the sequence on the Y-axis. Not sure if he didn't notice or didn't care. Probably didn't care, he was just having fun...so were we :-)
The box seems small in an Extra 300L, at least to me it does. At 180 KIAS you cross the entire box in a little over 12 seconds with no wind.
I would love to see a T-28 do it, Trojan is a favorite of mine.
How big is an aerobatic box just out of curiosity?
From rev. Jim memory, 1000 meter cube.Quote:
Originally Posted by steveinindy
The box is 3300 feet long, 3300 feet wide and 3300 feet tall.
That's it?! It makes you guys control of your aircraft all the more impressive.
depends I think - if it' s primary - sportsman etc.... it was noted above the sportsman box was 3500 cubed. feet. 3500 x 3500 x 3500. I believe correct me if I'm wrong it gets smaller and smaller moving int Advanced - and unlmiited. catagories. I fly also fast at about 160 - 190mph - and same as the 300L - it's flying right out of the box I also have to watch. I'm new at acro so I can make mistakes - it's what I seem to do best - but it's not important - what's important is that I do aerobatics and love doing it. I will get better and better at it - because I love doing it. I only started about 30hours ago. flying time. I took my first acro lessons the summer before last. Hooked on the first loop. Hope that helps - the IAC has an awesome website with lots and lots of good information you can download and print off etc... Whatever you do if you plan to do aerobatics get some professional instruction for sure. have fun but stay safe. frank.
The IAC contest box is 3300' x 3300', with a 164' buffer on each side, and then 3500' high for Primary, Sportsman, and Intermediate, 3609' (1100m) for Advanced, and 3280' (1000m) for Unlimited. BUT! Primary and Sportsman pilots may only fly down to 1500' AGL. Intermediate pilots may fly down to 1200' AGL. Advanced pilots may fly down to 656' (200m) AGL. Unlimited pilots may fly down to 328' AGL (100m). Confused yet? Advanced and Unlimited are consistent with international FAI CIVA rules.
So the box floor gets lower for the higher categories.
It is all in the IAC Official Contest Rules that you can find in the depths of the IAC web site.
Hope this helps,
Wes
N78PS
Thanks for the clarification - I'm new to aerobatics - or fairly new - and have yet to compete in a full IAC contest - I'm looking forward to my first contest though hopefully this fall up in Rocky mountain house. i will be in primary and hope to do sportsman as well. THanks again for sharing your experise and knowelge for us newbies.
I flew the T-28 in primary and it was the only airplane I have ever flown that took the entire box to dive to looping speed after the spin. What a hoot.
Adam
Here's a link to the IAC website. It shows the aerobatic box.
http://www.iac.org/images/begin/aerobatic_box-1.jpg
A T28 in competition? Now that would be neat to see. I really enjoy seeing different types at competitions. A couple of years ago a friend of mine flew a Tiger Moth in Primary and scored quite well (.5% behind a guy in a Giles 202).
Love seeing different types, particularly aeroplanes of the past back in the box. There is a chap that comes back every year to our Nationals in NZ to fly Sports in a 152 - does an awesome job too.
Basically anything with fabric and two sets of wings and you have my full attention. :)
I am no T-28 expert, only have about 20 min flying time in two different ones. I have seen someone years back do some good acro in one at a show. BUT a word to the wise, long time acro show pilot Julie Clark bought a T-28 about 10 years ago and she doesn't do a low level acro act in it.
I don't have any idea what stall/spin recovery is like in a 28, but I wouldn't want to find out near the ground.
To go to pretty much the opposite end of the scale, from dinosaur to feather; one of my favorite acro airshow acts was some years ago in California, maybe Minter Field, and was by a Curtiss Jenny. He did a spin, he began it at about 1000 feet and pulled out at about 600 feet. It was in such slow motion and so elegant that is seemed safe also. I still want to ride in and/or fly a Jenny.
Prom personal observation, a T-28 loses a good chunk of altitude in a spin.
There used to be a couple of T-Craft acro acts on the airshow circuit that started with multi-turn spins from relatively high. Took what seemed like a long time to come down and start figure 2.
If you want to see a true low performance, ground level aerobatic act, make a point of going to a John Mohr performance. He does a masterful routine in a stock 220HP no inverted system Stearman that stays stunningly close the the runway. If you want to see super energy management and a complete understanding of what the airplane can give you, his routine is a must-see. And his day job is captain for Northwest/Delta.
Fly safe,
Wes
N78PS
Let's just hope he never mixes the two up. LOLQuote:
And his day job is captain for Northwest/Delta.
Although I'd kind of like to see a 757 do a low inverted pass down show center at Oshkosh. It would be more interesting than most of the kerosene club performances.
A friend is also a NW captain. Due to the luck of the draw and scheduling, my friend did a 6mo check ride in the sim with John M. You can roll the sim. My friends roll was pretty bad compared to Mr Mohr's.
Fly safe,
Wes
N78PS
Think your friend could get me into the sim? I'd love to try that. LOLQuote:
A friend is also a NW captain. Due to the luck of the draw and scheduling, my friend did a 6mo check ride in the sim with John M. You can roll the sim. My friends roll was pretty bad compared to Mr Mohr's.