tag:blogger.com,1999:blog-5821522320379987891.post7514062403456060557..comments2023-11-11T18:21:04.799+01:00Comments on Shrediquette - the award-winning multirotors by William Thielicke: Aerodynamics in racing multirotors!William Thielickehttp://www.blogger.com/profile/01217178163189555726noreply@blogger.comBlogger19125tag:blogger.com,1999:blog-5821522320379987891.post-35746610355818325242022-02-09T08:07:02.934+01:002022-02-09T08:07:02.934+01:00They have improved a lot. But you have to keep in ...They have improved a lot. But you have to keep in mind that thrust decreases a lot with speed. And it is quationable if the "_static_ thrust to weight ratio" has a significant meaning at all.William Thielickehttps://www.blogger.com/profile/01217178163189555726noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-55403324550035915282021-12-07T01:33:43.101+01:002021-12-07T01:33:43.101+01:00"given that most racing quads have about 2.5:..."given that most racing quads have about 2.5:1"<br />Either that was wrong estimate or quads really improved that much over year<br />I did a carry capacity test on my Nazgul5 V2 and I got ~6:1 ratio and it's freestyle quad. I have seem people claiming 12:1 on racing quads and I just found this dude claiming 15:1 on ultralight build https://www.youtube.com/watch?v=Wy5VcDFdb6E&ab_channel=TheRCAddict<br />That's insane!Combinacijushttps://www.blogger.com/profile/14898843012531452397noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-1285184666490081152019-06-28T20:10:54.622+02:002019-06-28T20:10:54.622+02:00I'll admit I haven't read the entire artic...I'll admit I haven't read the entire article *yet*! But I have been thinking about this issue, too. My conclusion was that the bodies currently produce downward thrust at high speeds; but if you rotate the body 90° up, it could actually produce upward lift. There have been some speed record breaking quads that incorporate this. Interesting stuff!!<br />Now back to reading, lol ;)Lievenhttps://www.blogger.com/profile/14051099581193120372noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-62041701170528521582018-04-02T17:49:20.792+02:002018-04-02T17:49:20.792+02:00How DERBE is more crash proof than QRC5?(It doesn&...How DERBE is more crash proof than QRC5?(It doesn't look like that for me)Anonymoushttps://www.blogger.com/profile/01517637688500473623noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-14379335605331948862018-04-02T17:47:20.544+02:002018-04-02T17:47:20.544+02:00This comment has been removed by the author.Anonymoushttps://www.blogger.com/profile/01517637688500473623noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-54638972537516825232016-03-11T09:21:39.617+01:002016-03-11T09:21:39.617+01:00I think your blog is very powerfull to me. We have...I think your blog is very powerfull to me. We have hope that u can keep up the good job. Will u please take a look at our page also?<br /><a href="http://auto-sonnenschutz.ch/" rel="nofollow">scheibenfolie für auto</a>Boris1Whitehttps://www.blogger.com/profile/13749496027352652266noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-68804949477484116822015-12-28T10:58:43.989+01:002015-12-28T10:58:43.989+01:00Your posting provide an exclusive information, I a...Your posting provide an exclusive information, I appreciate this post. Thanks for sharing thisAeromodellinghttp://www.rcbazaar.com/noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-58304275101424880752015-10-31T06:46:33.723+01:002015-10-31T06:46:33.723+01:00First, awesome work. I can appreciate the time it ...First, awesome work. I can appreciate the time it must take to work on this as a hobby plus handling everything else!<br /><br />Maybe slightly off topic but have you ever considered developing you frame with a material similar to the HMB-235? I mean you do intend to have the thing going 100km/h + so would it not be cool if you could take a good hit and not worry too much? Not sure if you have seen that frame in action but its crazy durable! Hope you don't mind I link it here. Plain quad design but with your skills you could shape that material into something beautiful!<br /><br />http://www.multirc.com/products/27/HMB-235<br />navderekhttps://www.blogger.com/profile/01826419036172826482noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-67316359090819866452015-09-01T07:23:11.288+02:002015-09-01T07:23:11.288+02:00Anyway, totally missed you mention that. Anyway, totally missed you mention that. crashsalothttps://www.blogger.com/profile/11728958407229178597noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-61149497077129693322015-09-01T07:18:22.000+02:002015-09-01T07:18:22.000+02:00Of course you can do that with speeds, that's ...Of course you can do that with speeds, that's how navigation of planes and ships works.crashsalothttps://www.blogger.com/profile/11728958407229178597noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-78083436518806975012015-09-01T02:32:39.795+02:002015-09-01T02:32:39.795+02:00I had also thought that another consideration is t...I had also thought that another consideration is the resonant frequency of the arm material since vibrations are most pronounced on the plane of the propeller. I'm not an engineer so I do not know the correct terminology but vibration in this plane would tend to flex the arm in its weakest direction. has this issue presented itself?<br /><br />I designed a concept like this but I turned all of the electronics (naze32, etc) in their sides. Of course, the battery still presented a large face to the airflow. sam @http://fig99.comnoreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-25425420090863253232015-08-31T23:40:12.369+02:002015-08-31T23:40:12.369+02:00David Windeståls Minitricopter has been GPS logged...David Windeståls Minitricopter has been GPS logged doing 169 km/h so Im not sure it is an overestimation William :) THe MiniTri also has very little front area<br /><br />BR/ KajakenKajakmannenhttps://www.blogger.com/profile/07438800434467741984noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-35460745575942700592015-08-31T23:09:22.546+02:002015-08-31T23:09:22.546+02:002: yes that would very slightly increase the thrus...2: yes that would very slightly increase the thrust, because the flow is faster below the prop (because it contracts).<br />1: If you know the thrust at the specific speed you're flying at , then you can calculate what pitch angle would be best. But thrust decreases with speed, that makes everything a bit more complicated...William Thielickehttps://www.blogger.com/profile/01217178163189555726noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-85620328526633926042015-08-31T23:04:31.559+02:002015-08-31T23:04:31.559+02:00170 km/h surely is an overestimation as I also men...170 km/h surely is an overestimation as I also mentioned in the text.<br />Your approach to calculate the speed is not correct as far as I know. You can calculate forces in this way but I don't think you can do that with velocities... But I am traveling right now and can't think about this in more detail...William Thielickehttps://www.blogger.com/profile/01217178163189555726noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-57632502414073958172015-08-31T23:01:05.132+02:002015-08-31T23:01:05.132+02:00Hi, I don't know yet... But the laser sintered...Hi, I don't know yet... But the laser sintered parts do not really add weight, they're light and super robust.William Thielickehttps://www.blogger.com/profile/01217178163189555726noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-47743429037762042892015-08-31T22:42:51.503+02:002015-08-31T22:42:51.503+02:00Dr-
I have been thinking about this for some time ...Dr-<br />I have been thinking about this for some time and I have 2 points/questions to pose:<br />1) given that most racing quads have about 2.5:1 lift to weight ratio, then flying at 45deg seems inefficient. If you apply full throttle, you would climb too much if you were only pitched 45deg.<br />It would seem that, to maximize the available power, you would have to fly at an angle of attack that is 2.5:1 off of vertical. This is more like 75deg (maximum). Does this sound right?<br />2) The airflow coming from the props is helical. while you gain much efficiency by using your vertically oriented arms, do you waste some of the energy when those arms "divert" some of the propeller wash? would it be better to place the arms above the props to allow the flow off the propellers to flow as uninterrupted as possible?sam @http://figg99.comnoreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-55737490449564282122015-08-31T22:29:59.274+02:002015-08-31T22:29:59.274+02:00Quick question: Vpitch for a 4" pitch prop is...Quick question: Vpitch for a 4" pitch prop is around 220km/h (2300kv*16V*4"); isn't Vmaxhorizontal at a 34 degree pitch of the copter sin(34)*220=125km/h? Or is that approach too simple? that is even without any drag. just wondering how your results are showing 170km/h for the Derbe....crashsalothttps://www.blogger.com/profile/11728958407229178597noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-16916986739542570352015-08-31T22:19:37.432+02:002015-08-31T22:19:37.432+02:00What's the weight of the DERBE?What's the weight of the DERBE?Hugohttps://www.blogger.com/profile/15798662306904343539noreply@blogger.comtag:blogger.com,1999:blog-5821522320379987891.post-42253796550974165452015-08-31T21:28:38.316+02:002015-08-31T21:28:38.316+02:00Nice Article!
I also wonder if or better HOW the d...Nice Article!<br />I also wonder if or better HOW the different angles showup on a racetrack - unfort. I also think about different angles for front and rear motors and how this affects the flyability...<br />Hard to explain by words but if you have more angle on the rear and a flatter fron angle the rearmotors should more push and due to the punch the front motors more responsible to let the racer keep on level...<br />Or as I also saw in Bexbach the try to have a more bended angle to the outside as acro quads...<br /><br />It's hard to say whats better... For just fly straight maybe but on a track where you can't suffer from long straight trackparts you might loose much punch in the turns...<br /><br />But I like that someone starts over and trys to calc the behaviour!<br />thx!Freakhttps://www.blogger.com/profile/08542726020931520409noreply@blogger.com