SAE Heavy Lift
#1
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SAE Heavy Lift
Congrats to the University of BC and the University of Windsor teams in winning the SAE competitions. [link]http://www.rccanada.ca/bb/viewtopic.php?t=14821[/link].
This is a great example of achieving excellence even thought this was not an Aero Club of Canada or FAI contest and was probably done without the usual begging for a MAAC handout.
Congrats again!
This is a great example of achieving excellence even thought this was not an Aero Club of Canada or FAI contest and was probably done without the usual begging for a MAAC handout.
Congrats again!
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RE: SAE Heavy Lift
ORIGINAL: kenair
... even thought this was not an Aero Club of Canada or FAI contest and was probably done without the usual begging for a MAAC handout.
... even thought this was not an Aero Club of Canada or FAI contest and was probably done without the usual begging for a MAAC handout.
Your hatred of the Aeroclub, FAI and all things competition is both tiresome and annoying. Back under your rock.[>:]
Marc, you need hunt no further, I've found your Loogan.
#4
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RE: SAE Heavy Lift
Is this cr*p really necessary?
Your hatred of the Aeroclub
Your hatred of the Aeroclub
Give these students some credit, they actually had to compete against other teams to achieve thier standing, unlike some MAAC team trials where just showing up allows the individual a placement or win.
Jim, I really think you need to stop these personal attacks on individuals that do not agree with your point of view, your comments are immature and do not allow for the open debate on maac issues. I think an apology from you is in order.
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RE: SAE Heavy Lift
I apologize ... to everyone reading this other than you Ken.... I should know better than to feed the trolls.[:'(]
... and thanks for the suggestion, I think I will go congratulate the students ... on the original thread on the site your were banned from for trolling.
#6
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RE: SAE Heavy Lift
.......man, you dragging me down with you again Ken?
................throw me a line [sm=drowning.gif]
We don't even live in the same province.........
............not like I had beers with the guy last night!
[sm=biggrin.gif]
Like our fearful leader, Mr. DithersMartin, I shall not take a stand on this issue..........
..........unless the appropriate amount of cash is slipped to me third-hand via envelope and that 50% of the envelopes contents are burned and, thus distributed to the environment, as approved by Jack Lay(medown)ton!
This is a stand that I firmly think I might maybe take on such issues.
................throw me a line [sm=drowning.gif]
We don't even live in the same province.........
............not like I had beers with the guy last night!
[sm=biggrin.gif]
Like our fearful leader, Mr. DithersMartin, I shall not take a stand on this issue..........
..........unless the appropriate amount of cash is slipped to me third-hand via envelope and that 50% of the envelopes contents are burned and, thus distributed to the environment, as approved by Jack Lay(medown)ton!
This is a stand that I firmly think I might maybe take on such issues.
#7
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RE: SAE Heavy Lift
Wow, a friend pointed out this thread to me today, and I'm amazed how fast it got off topic.
Anyhow, on behalf of the UBC guys, thanks for your kind words of support!
I'm the pilot for UBC, and the guy that posted the original thread on RCCanada. That plane was awesome to fly with 48.8lb on board, and a little nerve racking with a damaged prop! That flight was in the 2nd to last round of flights on the final day. In the last round, we had ~58lb loaded into it (more that the scale could measure) just in case another team scored what we thought was a competitive flight. Based on the 48.8 lb flight characteristics and the numbers we ran at that density altitude, the 58lb would have been tough but doable. This kind of competition sure teaches a pilot a LOT about energy management in R/C models. With 58lb on board, that would have been a payload:aircraft weight ratio of just over 6:1. That's way up there in terms of the SAE contest history from what I've heard. the 48.8 lift was just over 5:1.
The team managers, other team advisors, and myself just had a meeting with the faculty today. Needless to say, the school is overjoyed with the results and we hope to create another competitive entry next year. These competitions are more fun that any fun fly or R/C meet I've ever been to. If you ever get the chance to fly for an SAE Aero design team, go for it!
Kelly
Pilot/advisor for UBC Open Class
Anyhow, on behalf of the UBC guys, thanks for your kind words of support!
I'm the pilot for UBC, and the guy that posted the original thread on RCCanada. That plane was awesome to fly with 48.8lb on board, and a little nerve racking with a damaged prop! That flight was in the 2nd to last round of flights on the final day. In the last round, we had ~58lb loaded into it (more that the scale could measure) just in case another team scored what we thought was a competitive flight. Based on the 48.8 lb flight characteristics and the numbers we ran at that density altitude, the 58lb would have been tough but doable. This kind of competition sure teaches a pilot a LOT about energy management in R/C models. With 58lb on board, that would have been a payload:aircraft weight ratio of just over 6:1. That's way up there in terms of the SAE contest history from what I've heard. the 48.8 lift was just over 5:1.
The team managers, other team advisors, and myself just had a meeting with the faculty today. Needless to say, the school is overjoyed with the results and we hope to create another competitive entry next year. These competitions are more fun that any fun fly or R/C meet I've ever been to. If you ever get the chance to fly for an SAE Aero design team, go for it!
Kelly
Pilot/advisor for UBC Open Class
#8
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RE: SAE Heavy Lift
...wow.
Well Done Kelly.
Is there a link to the site where we can see some pictures of the plane?
Did you folks discover something "new" in wing design/airfoil ect. to get to that 6:1 ratio or was it more a case of construction materials that made it stronger and lighter?
Well Done Kelly.
Is there a link to the site where we can see some pictures of the plane?
Did you folks discover something "new" in wing design/airfoil ect. to get to that 6:1 ratio or was it more a case of construction materials that made it stronger and lighter?
#9
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RE: SAE Heavy Lift
No, there really wasn't anything distinctly new about the design. I think the key to the strategy for this year was the 10lb maximum empty weight, as apposed to last year's optimum weight with a max displacement rule.
Taking a step back... Last year, there was a max displacement of 0.92 cu in, using however many engines you wished to use, of any brand, modified or stock, etc... Some teams went with .91 2-strokes and optimized the prop, added gearboxes, etc... The really competitive teams used a pair of Jett 46's with tunes exhausts. The top 2 (Akron and Missouri-Rolla) both had variations of this combo. They were achieving in the range of 22lb of static thrust with custom modified Bolly props, large diameter and very low pitch.
Now on to this year...
Both of these teams used Jett engines again, Acron used the same engines as last year, while Rolla switched to a brand new set of BSE 60's since the weigh increase was negligible. (ironically, our team's Jett 76L was lighter that a 60, although the reliability may have been an issue from pushing a 46 size crank case so far...) Each of those teams then proceeded to optimize their last year's concept by reducing the weight down from ~14lb to ~10.
UBC's approach was a clean slate, using absolutely nothing from last years design as it really wasn't competitive. The first thing they nailed down was a strict weight budget. We all sat down together and ran numbers of what each control surface, fuselage component, etc should weigh, and they stuck to it as best they could. If a component came in over budget, it was scrapped or in some cases the budget was deemed to be inaccurate and therefore it was adjusted. This is basically the way things are done on the real thing so it proved to be an excellent learning experience for them. When considering the budget, it became evident that they could get 2 of these marvellous Jett BSE Fire 76L engines (@13oz each+pipe and hardware) and achieve 30+ lb of thrust! The downside is the amount of weight it consumed from the budget, although it was tempting to do a twin. The chosen alternative was go with the best 'power to weight' option available (the Jett 76L) and make the best (larger and most efficient) wing possible... In the grand scheme of things, wing loading is the number 1 factor, raw thrust is 2nd according to the 2005 rules... More engine would still produce a competitive aircraft, but takeoff and landing speeds would go way up by the calculations, due to the proportionally smaller wing.
The wing was constructed from a small carbon spar on top and bottom. The spars were spaced apart by a closed-cell PVC foam structure and a layer of fibreglass (vac bagged in place with epoxy) was utilised as a shear web on each side of the foam. the wing eventually came out to just under 4lb and we estimated its strength to be in the range of 200lb of payload centrally mounted. The entire design was done to accommodate a 4g gust or landing load. The wing was a multi-tapered design that had a tremendous chord in the centre section, thus allowing a very large moment of inertia in the spar. The guys also spent a great deal of time analysing airfoils and came up with a very effective lifting surface, although the downside was suppose to be a nasty tip stall tendency. I had to stay conscious of the tip stall threat and use spoilers at the tips to avoid stall at times.
The fuselage was constructed primarily of the same carbon used in the spar. It was built as a long truss, optimized in the cross member placement by a larger iterative spreadsheet that calculated the buckling case in each position. As the lengths changed, the truss member positions changed, thus changing the lever arm from the tail surface, again changing the buckling case... They then used a few analysis techniques to appropriately size the Kevlar webs across each truss segment and built it to comply with torsion case from max deflection of the rudder and elevator at the 'do not exceed' speed limit. The fuse weighed in at ~1 lb.
Overall, it was an exercise in optimizing and eliminating redundant material. Use of Kevlar, carbon fibre, THIN plywood, and a variety of appropriate industrial adhesives (from Loctite-Canada, a sponsor...) were some of the keys to the deign.
I'll post more pictures in the RCCanada thread, linked in the 1st post of this thread.
Kelly
Taking a step back... Last year, there was a max displacement of 0.92 cu in, using however many engines you wished to use, of any brand, modified or stock, etc... Some teams went with .91 2-strokes and optimized the prop, added gearboxes, etc... The really competitive teams used a pair of Jett 46's with tunes exhausts. The top 2 (Akron and Missouri-Rolla) both had variations of this combo. They were achieving in the range of 22lb of static thrust with custom modified Bolly props, large diameter and very low pitch.
Now on to this year...
Both of these teams used Jett engines again, Acron used the same engines as last year, while Rolla switched to a brand new set of BSE 60's since the weigh increase was negligible. (ironically, our team's Jett 76L was lighter that a 60, although the reliability may have been an issue from pushing a 46 size crank case so far...) Each of those teams then proceeded to optimize their last year's concept by reducing the weight down from ~14lb to ~10.
UBC's approach was a clean slate, using absolutely nothing from last years design as it really wasn't competitive. The first thing they nailed down was a strict weight budget. We all sat down together and ran numbers of what each control surface, fuselage component, etc should weigh, and they stuck to it as best they could. If a component came in over budget, it was scrapped or in some cases the budget was deemed to be inaccurate and therefore it was adjusted. This is basically the way things are done on the real thing so it proved to be an excellent learning experience for them. When considering the budget, it became evident that they could get 2 of these marvellous Jett BSE Fire 76L engines (@13oz each+pipe and hardware) and achieve 30+ lb of thrust! The downside is the amount of weight it consumed from the budget, although it was tempting to do a twin. The chosen alternative was go with the best 'power to weight' option available (the Jett 76L) and make the best (larger and most efficient) wing possible... In the grand scheme of things, wing loading is the number 1 factor, raw thrust is 2nd according to the 2005 rules... More engine would still produce a competitive aircraft, but takeoff and landing speeds would go way up by the calculations, due to the proportionally smaller wing.
The wing was constructed from a small carbon spar on top and bottom. The spars were spaced apart by a closed-cell PVC foam structure and a layer of fibreglass (vac bagged in place with epoxy) was utilised as a shear web on each side of the foam. the wing eventually came out to just under 4lb and we estimated its strength to be in the range of 200lb of payload centrally mounted. The entire design was done to accommodate a 4g gust or landing load. The wing was a multi-tapered design that had a tremendous chord in the centre section, thus allowing a very large moment of inertia in the spar. The guys also spent a great deal of time analysing airfoils and came up with a very effective lifting surface, although the downside was suppose to be a nasty tip stall tendency. I had to stay conscious of the tip stall threat and use spoilers at the tips to avoid stall at times.
The fuselage was constructed primarily of the same carbon used in the spar. It was built as a long truss, optimized in the cross member placement by a larger iterative spreadsheet that calculated the buckling case in each position. As the lengths changed, the truss member positions changed, thus changing the lever arm from the tail surface, again changing the buckling case... They then used a few analysis techniques to appropriately size the Kevlar webs across each truss segment and built it to comply with torsion case from max deflection of the rudder and elevator at the 'do not exceed' speed limit. The fuse weighed in at ~1 lb.
Overall, it was an exercise in optimizing and eliminating redundant material. Use of Kevlar, carbon fibre, THIN plywood, and a variety of appropriate industrial adhesives (from Loctite-Canada, a sponsor...) were some of the keys to the deign.
I'll post more pictures in the RCCanada thread, linked in the 1st post of this thread.
Kelly
#10
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RE: SAE Heavy Lift
Thank Kelly. Very interesting.
....Sounds like the Burt Rutan school of design. I read an article recently in which they were expaining how they decided if a particular part of their successful globeflyer was light enough............
......they would throw the part up in the air.........if it came down...................It was too Heavy.
I'll check out the pics.
....Sounds like the Burt Rutan school of design. I read an article recently in which they were expaining how they decided if a particular part of their successful globeflyer was light enough............
......they would throw the part up in the air.........if it came down...................It was too Heavy.
I'll check out the pics.
#11
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RE: SAE Heavy Lift
Like our fearful leader, Mr. DithersMartin, I shall not take a stand on this issue..........
..........unless the appropriate amount of cash is slipped to me third-hand via envelope and that 50% of the envelopes contents are burned and, thus distributed to the environment, as approved by Jack Lay(medown)ton!
This is a stand that I firmly think I might maybe take on such issues.
cute Marc!!...thanks for the chuckle this morning!!
I would also like to pass on my congratulations to the UBC and UW teams! Well done.
Ron
..........unless the appropriate amount of cash is slipped to me third-hand via envelope and that 50% of the envelopes contents are burned and, thus distributed to the environment, as approved by Jack Lay(medown)ton!
This is a stand that I firmly think I might maybe take on such issues.
cute Marc!!...thanks for the chuckle this morning!!
I would also like to pass on my congratulations to the UBC and UW teams! Well done.
Ron
#15
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RE: SAE Heavy Lift
A few pictures of UBC's plane in testing and down in Texas.
Kelly
PS:
As said in the RCCanada thread, many thanks to the following sponsors in 2005: [sm=thumbup.gif]
Creo Inc (www.creo.com)
Aerial Innovations
Norburn Hobbies (www.norburnrc.com)
Hiflight RC (www.hiflightrc.com/html/home.html)
Loctite Canada / Hysol adhesives (www.loctite.com)
Pitt Meadows Airport (www.pittmeadowsairport.com/)
Kelly
PS:
As said in the RCCanada thread, many thanks to the following sponsors in 2005: [sm=thumbup.gif]
Creo Inc (www.creo.com)
Aerial Innovations
Norburn Hobbies (www.norburnrc.com)
Hiflight RC (www.hiflightrc.com/html/home.html)
Loctite Canada / Hysol adhesives (www.loctite.com)
Pitt Meadows Airport (www.pittmeadowsairport.com/)