RE: 200mph electric delta brainstorming
A 200 mph F5D should stay under $1000 unless you go for one of the high end airframes. And about 1KW will do it. The current crop of F5D can not hold enough battery to hit 230-260. If you tried, you would be replacing a puffed pack almost every flight. There are some speed cup type planes that are available, one called Ninja Speed that can hold the power, but you must build it from plans. External mounted big outrunner running a prop like the one I linked above. 6-8 KW and about 240-250 if you don't blow it up. The high aspect F5D turn at very high speeds and maintain speed. Turn deltas at at high speed (necessary to keep them in sight) and you scrub speed in the turns that you are always hitting that wall. Deltas under 200 go very fast, cheaply. Start getting close to 200 and you use so much energy in the turns that only shear HP will get you a tiny bit more. High aspect ratio maintains much more in the turns. I know....I currently fly an Enigma F5B, 4KW hotline, 175 flat and level, no dives, 200+ Power on dives. [X(] I also fly a 600 watt Sunracer III 1M F5D (old rules) It is a solid 160. I have flown 200 mph Deltas and flew A LOT of 150+ deltas. They are the fastest and slowest planes at most any field. Cheap, simple, and good honest flying airplanes. You can do some crazy thing with them like....150 mph knee cap pass, even with your self, kill engine as pulling full back. Delta does a decelerating, 50-75 foot fibonacci loop followed by a walking speed, high alpha belly flop at your feet. Nuff said....... Brooks
Posted on: 5/17/2013 8:01 PM by Author "bpbrinson" in the forum "Extreme Speed Prop Planes"
http://www.rcuniverse.com/forum/fb.asp?m=11514784

RE: 200mph electric delta brainstorming
swing this! Gonna need a fair amount of wattage...........and a gearbox. http://www.soaringusa.com/GM-10x23-30-5mm-Set.html
Posted on: 5/16/2013 9:01 PM by Author "bpbrinson" in the forum "Extreme Speed Prop Planes"
http://www.rcuniverse.com/forum/fb.asp?m=11513864

RE: Maximum altitude??
"Hemmorage of airspeed" = induced drag. There is no difference between hard turns and slow flight only airspeed. High AOA that is required to fly a delta (tailless) slowly requires lots of power. "Glide" at lower airspeeds for deltas is very steep. Wake turbulence that the pusher has to "chop" through is the reason for lower efficency. Also the other downside of pushers is that they usually have to spin a lower A/R propeller (diameter) due to interference issues with airframe structures and the ground at rotation. Loss of efficency. The beauty of electric is when you want a sample period, turn the motor off. If it is a sailplane type platform you have, glides can be well over 50:1. @Iron, Tell that to the guys that fly their sailplanes over 400mph....oh, nevermind they do blow them up[:D]. We are flying our "powered sailplanes" over 150, even 200mph without the issues you describe. Visit the "High Performance" forums on RCGroups. My deltas I designed 20 years ago, needed 2KW (glow) to get in the neighborhood of 180 and the "sailplanes" of about the same size only need 1KW to break 200. Yeah, build them out of wood, they explode. Composite is the only way to go. Brooks
Posted on: 4/3/2012 1:53 PM by Author "bpbrinson" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=11026833

RE: Maximum altitude??
No, never said horrible, run as big and slow turning a prop as as possible. Keep it as clean and smooth as possible ahead of the propeller. I will volunteer to make power plant suggestions when you get to that point. I will need final airframe dimensions, weight, desired airspeed in flight, max alt. desired, ground and structure to centerline of shaft dimensions so I can suggest the correct propeller/gearbox/motor/esc/batteries. All will be off the shelf, (internet) equipment. But it must be final or near final numbers. This stuff is not cheap. Need to only buy once. Be sure, if going to pusher, that the dimension includes distance shaft to ground at maximum rotation angle. Always have a seperate battery and switch for flight and other onboard systems (no BEC). If things fry, you still want to see and glide. I send a nice spreadsheet. Free of charge. Brooks
Posted on: 4/3/2012 12:08 PM by Author "bpbrinson" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=11026894

RE: Maximum altitude??
RG is correct. The projects that I consulted and flew, had to be flown in restricted airspace. Controlled military base. We were also required to have a recovery parachute. The parachutes purpose was not to save the aircraft, but to stop flight in case it flew out of control and restricted airspace and caused a threat to public/ risked capture. Lets just say the biggest I test flew, took a 16 ft chute to stop flight. If we needed to use it, we would have had a crash site covered with a parachute. Current laws MAY have exceptions. Texas A&M have experience in all sizes of UAS. Ask them. Trust me, Pattern, you guys are not the 1st to do things like this, save yourself some time/money/failure and ask for help from your fellow universities. This is not a football rivalry. Brooks Skirting on the edge of saying too much.
Posted on: 4/3/2012 11:28 AM by Author "bpbrinson" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=11026846

RE: Maximum altitude??
1st question is always " What do you want to carry and what do you want to do with it?" I was simply trying to get to that. You have been very vague, but asking for help. There are some professionals on this forum that have been doing this for decades (30 years for me). Answers like "I have my reasons" are not helpful for you or anyone that does this type of thing for pay, but is volunteering our services. Your title "Maximum Altitude" is not accurate as to your goals, obviously. Yes, high aspect ratio is the answer and is the most flexible as to speed range, deltas are effecient in a more limited range. Pusher is structurally problematic and a bit less efficient. There are some pusher folder spinners on Esprit Models website. That is all I have for you with the information you have provided. Brooks the gift horse
Posted on: 4/3/2012 10:11 AM by Author "bpbrinson" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=11026740

RE: Maximum altitude??
@ 1 oz of lift per Cubic foot of helium(not counting weight of containment) this will get huge just to help carry a fraction of the weight. Doable and good idea, but gonna get real big to make any difference. Bigger=more drag = more power to move = heavier=more power=heavier....... 80 cubic feet to carry 5 lbs, not counting weight of containment. Now you gonna build a blimp or an airplane? Both may work. Brooks
Posted on: 4/3/2012 8:10 AM by Author "bpbrinson" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=11026574

RE: Maximum altitude??
"Anything else im leaving out?" Designing an airframe before or without payload data and sample requirements is kinda putting the cart before the horse. Please, more detail as to equipment and sample requirments. Brooks
Posted on: 4/3/2012 7:56 AM by Author "bpbrinson" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=11026542

RE: Maximum altitude??
I have worked as a consultant for many years on UAS projects. If you could be more specific as to payload/equipment, perhaps I/we could be more help. I have seen a project that resembles what you may be describing. In the late 90's, a group of UT students brought out a 1 meter square fine nylon"screen" in a pvc pipe frame to my dropzone and asked/hired a couple of skydivers to freefall with it. Never heard the results, but did see some very small spiders w/web and a grasshopper in the screen. I could see the problems w/ that method, took several thousand feet for the skydivers to get it stable (huge drag). The "vertical sample" being the biggest problem to sort out. Contamination from close to ground during landing. Loss of material if not handled properly by the skydiver landing with it (turned backwards) ect... More details would be helpful. Brooks BTW, my wife is a LSU '90 grad, CJ degree
Posted on: 4/3/2012 7:26 AM by Author "bpbrinson" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=11026501

RE: Maximum altitude??
You could "re-invent the wheel" which is fun but often gets in the way of the real project. Or you could purchase this UAS and/or consult Skip Miller Models in Colorado. He has worked w/ several universities. The Tempest has more than enough room for all your FPV/telemetry and anything else you want to stuff in it. Designed just for the type of project that you describe. http://www.youtube.com/watch?v=N8Lb9TSKuV4&feature=BFa&list=UUpXEyOvnKV3r4M5RKRiJ5vA&lf=plcp http://www.skipmillermodels.com/ http://uasusa.com/ "recently achieved a very successful mission with flights exceeding upward of 10.8 miles above the surface of the earth..... and returned safely to the launch site 38 miles upwind." 57,000 Feet!!!! I am sure with UASUSA's background working w/ universities would give a leg up in the approval process w/LSU. Brooks
Posted on: 4/3/2012 5:19 AM by Author "bpbrinson" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=11026301

High Speed Flying sites
Looking for a club in Northern Virginia that is speed friendly and have no "special rules" for fast and low planes. I moved here about 8 months ago from Texas and am about to go looking for another new club (third). 1st one was treed in and flapless pylon was almost imposible to land w/o damage. The other says fly the otherside of the runway except for me. I have to stay 50 yds beyond that over 20 ft trees. That is w/ my hotliner. They have not seen my pylon stuff yet. Safety officer is skeerd[X(]. Brooks
Posted on: 3/19/2012 1:20 PM by Author "bpbrinson" in the forum "Extreme Speed Prop Planes"
http://www.rcuniverse.com/forum/fb.asp?m=11007231

RE: Surface Drag
From personal (literally) experience, I skydived for many years and had several suits for different disciplines. I had a fast suit (belly to earth) for when I was skinny that was made of nylon and was fairly tight. A cotton and cordura suit that was fairly tight also for slower fall rates (had to buy this one for when I became heavier and more bullet shaped). I had a loose cotton suit for head down, sit, and standing (freeflying). I had a "Pro ditter" that would record fall rates and belly with skinny suit i fell as slow as 125 and as fast as 170. 170 was flying with freeflyers, belly with elbows in and fists in chin with heels in my ears. My slow belly suit I could slow to sometimes slower than 110 and as fast as 140. Freeflying is a whole other story, have gone 225 in a stand. So, at those speeds the fabric made a huge difference in speed. By the way, in a track, we could go close to 100 mph horizontal and the slowest vertical in a track I went was 94. Had to really make your body into a wing. Brooks
Posted on: 7/21/2011 9:39 AM by Author "bpbrinson" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=10631950

RE: Great Planes Rifle
I used your guide (up to 600w) as the reference for upper vs. lower, however I have seen a "stock" (Ammo is all he said) break on a very abrupt pull up. I just realized that you "have a dog in the hunt" being Hobbico and all. So, no offense Tim. The Rifle is a good mainstream product within the limits of the specifications. I was just reporting what I had witnessed and I know how speed guys are, more is better. Myself, being a speed guy for almost 25 years, have broken many airframes in the air over the years due to exceeding the manufacturer specs. I was just giving the folks that frequent this forum a choice in airframes that I found years ago that can handle as much as can be stuffed in them. Brooks
Posted on: 6/20/2011 9:39 AM by Author "bpbrinson" in the forum "Extreme Speed Prop Planes"
http://www.rcuniverse.com/forum/fb.asp?m=10583573

RE: Great Planes Rifle
The Rifle WILL break at the upper power levels. Even at the lower levels if you pull too hard. The Pylon models in this link will not break at any power level or flying style. The ones in the 30 inch class were the old speed 400 class. The 1 meter (40 inch) were the old F5D and the 50 inch are the current F5D class. F5D racers are turning 4.75X4.75 props close too 50,000 rpm and exceed 200 mph in straight runs easily. http://www.soaringusa.com/products/subcategory.htm?category_id=265 Brooks
Posted on: 6/20/2011 8:32 AM by Author "bpbrinson" in the forum "Extreme Speed Prop Planes"
http://www.rcuniverse.com/forum/fb.asp?m=10583479