It probably going to have one fan for the lift and two for steering, each powered by seperate motors. The lift fan will have a separate battery pack to the two for steering as it'll be on more. Erm, as for the RC I'm not sure at the moment, maybe take apart an old rc car controller of something, or maybe buy a tradio transmitter with several recievers. Do you happen to know where I could get something like that quite cheap?
If I were you, I'd look for a local hobby shop. I found one near my house that could sell you virtually every piece of your project. Pay particular attention to model aircraft parts/kits - they contain powerful little engines (many run on gas) and propellers.
Most of my "calculating" was trail and error. i.e. trying different skirt materials to see which one works best. Sketch the whole design out on paper with measurements beforehand. My only real number-crunching had to do with the propeller/engine but since you're working on a smaller scale, you probably don't have to be as meticulous. Keep it light - that's my best advice. How are you planning to power it and do the RC?
Wow, sorry for the delayed response - I didn't see your comment. I couldn't tell you exactly how much it cost because it was a birthday present. (Yes I asked for a propeller for my birthday.) But I do know it was purchased on Ebay. Sorry I can't give you more info.
was i being rude? i was just stating that you don't have to use big words etc to be smart.and just curious, why would torque matter? isnt it with speed that you should be more concerned about?
No, the speed is important but it is not the decisive factor affecting the machining precision. Torque is dependent on the rotational force applied and the length of the lever arm. My prop has much more mass than yours and is much, much longer. This requires more torque to make it do 1600 RPMs. It is that extra torque that amplifies the effects of an alignment error. Sensenich, the manufacturer of the propeller can confirm that for you; they did for me.
When you are spinning it at 1600 RPMs, you had better be precise to the 1,000th of an inch or you're generating several newtons of off-axis force. That would eventually rip the propeller off the shaft or worse: the entire engine. If you tried your 'method' you would wind up dead. I don't say things without reason.
Dude, what are you talking about? I run a 20 HP engine on a hovercraft with 1/8 clearance and there is no issue with "off-axis" force. I appreciate what you've done, but you don't do yourself any favors by trying to seem more knowledgeable than you are.
I am not trying to be pretentious, or cocky, or "seem more knowledgeable than I am" and I honestly don't know why you think so. All I am saying is that for my application I needed to machine my flange precisely. This is both based on my calculations and the guidelines of the propeller manufacturer. I would imagine that you are using a pre-made flange that is already CNC machined to precise specs. I made mine myself and I wanted to minimize any chances of error.
lol you must really think you are smart. i will post a vid in a week or two of my "lathe" and "drill press". but you really think that .0005" off will matter? i got an r/c plane, and im pretty dam sure the prop isn't that accurate, and it spins faster than 1600 rpm.
I don't think I'm nearly as smart as you think you are...
I do not just "think," I KNOW that it must machined be that precisely - it can be proven with very simple physical formulas. In fact, I had an in-depth conversation about it with a college professor/engineer who is an expert in this field and would be happy to back me up. I can share his email address with you if you would like to discuss this with someone of some authority.
Also, your r/c plane's engine operates with a mere fraction of the torque of my 2 HP engine and the propeller/flange is much smaller and lighter. Of course it doesn't have to be as precise. And as to your "you don't need college credentials or classes to be smart kid" comment, that is exactly what I meant by a "crude, useless comment." Keep posting garbage and I WILL delete it. I'll be happy to have a genuine discussion with you, but not if you continue to be so rude.
Yes, that's correct. It is a surprise. You got a job or did mommy and daddy pay for it? i just couldnt believe you spent that much for it. there isnt much there. i mean, yea, you finish with some green flames? im not trying to be a dick, i just didnt think you would spend that much for about nothing. MAYBE if you bought everything brand new. and shit if you spent that much, i woulda made it look a lot nicer. but then again i do a lot of projects myself, not requiring other peoples work hours
My parents payed for the majority of it, and I am very grateful that they did. For somebody who "does lots of projects" I am surprised that you underestimate the cost. There are multiple gasoline engines, an airplane propeller, custom CNC machining, and a heck of a lot of structural implements to make it safe and efficient. When you build a nicer hovercraft for less money then you can criticize me all you want. Until then, save your useless, crude remarks - they are helping no one.
Ebay. It's a Sensenich 29" diameter, 22" pitch wooden airplane propeller. Mounting hardware is not on the market so I had to custom CNC-machine a flange from steel stock to mount it on a 2HP small engine (also from Ebay). Unless you have access to VERY precise machining facilities, I DO NOT recommend this method. Try to find a propeller which already has mounting hardware included. Please let me know what you come up with.
hey, do you think two 31cc blowers @ 425CFM each can support a 4x5 foot platform at around 250 lbs? I'm currently also making a large-format hovercraft
Yes. I could get mine hovering with only one blower of similar size. Do your best to seal off any air leakage from the skirt. You can sprinkle some flour on the base of the hovercraft and run it to get a good sense of where any leaks might be. Be sure to buy plenty of duct tape! I recommend the system I came up with for securing the skirt- it's a few comments down from this one and very airtight. I wish you the best of luck! Post some video when you're finished; I'd love to see your work.
No I have not - it's not powerful enough yet. If I ever upgrade the lift engine to a ducted fan (like in the back) or add another leaf blower I'll give it a shot. For now, I'd rather stay dry :-)
The skirt is a PVC-reinforced canvas dropcloth bolted to the bottom of the base using a rounded plastic gutter cover. There are reinforced holes around the perimeter of the gutter cover. The edges of the skirt are sandwiched between adhesive weather stripping and 1/2" wooden molding strips screwed to the top of the base. Then they're taped down with duct tape. It's my own design and VERY airtight. Try varying the size and shape of the skirt; it can make a big difference in stability. Good luck!
That was awesome dajutser. Congratulations on a great design. It looks like you were just like us (although a little older) in that you just wanted to figure out how do it as much as to have it when you got done. The end product is killer. Thanks, too, for checking ours out. Are you going to do another?
No, I'm not going to make another one but I do hope to make some major improvements to this design. I'm just so busy! Some day I will, but for now it will sit in the basement :)
The steering on this thing looks really crappy. On the hovercraft I am building now I am using a thrust vectoring system that I found on the internet. Just google "hovercraft vector" and you can see how much better this is compared to flaps.
Homestly, it's not all that bad. The lift system is the crappy one :) The thrust vectoring you mention is interesting; the real advantage is the braking. Thanks for the tip and post some video of your finished hovercraft!
On my hovercraft I am using a smaller 31cc engine and an 18 inch prop but the engine is modified to run at 7000 rpm so I should get plenty of thrust. my lift engine is 2 leaf bloweres that each move 400 cfm so I'll have plenty of lift too.
Also, about the thrust vectoring.
If you use this system there is no need for throttling the thrust engine.
Thanks! It was primarily made just to prove to myself that I could do it and the end of the school year put an abrupt end to my project. You are entirely right in everything you said, and it all stems from using a cheap leaf-blower as the lift engine. If I replaced it with a ducted propeller it would greatly boost the performance and I'm confident it would work well on water. I need the money and the time... Maybe some day!
Oh also - you said that the contols could be improved. What did you have in mind? You would be surprised how effective the steering system is. Granted, the propeller's engine is near impossible to throttle. I need to add some form of reduction belt system to get more out of it.
wow thats really cool ! so in like 10 or 20 years do you think is will be well like for real ? and you'll be a millionaire with this idea lol i looks like so much fun does it still work ? i hope so cuz i want a ride lol :D tell Leah hi for me ttyl - Amelia
It probably going to have one fan for the lift and two for steering, each powered by seperate motors. The lift fan will have a separate battery pack to the two for steering as it'll be on more. Erm, as for the RC I'm not sure at the moment, maybe take apart an old rc car controller of something, or maybe buy a tradio transmitter with several recievers. Do you happen to know where I could get something like that quite cheap?
yellowblutac 3 years ago
If I were you, I'd look for a local hobby shop. I found one near my house that could sell you virtually every piece of your project. Pay particular attention to model aircraft parts/kits - they contain powerful little engines (many run on gas) and propellers.
dajutster 3 years ago
Very impressive! :) I'm looking at making one myself (a much smaller RC one mind) did you have to do many calculations before the build?
yellowblutac 3 years ago
Most of my "calculating" was trail and error. i.e. trying different skirt materials to see which one works best. Sketch the whole design out on paper with measurements beforehand. My only real number-crunching had to do with the propeller/engine but since you're working on a smaller scale, you probably don't have to be as meticulous. Keep it light - that's my best advice. How are you planning to power it and do the RC?
dajutster 3 years ago
may i ask wer did you get the airplane prop and how much did it cost
PyroManiac424 3 years ago
Wow, sorry for the delayed response - I didn't see your comment. I couldn't tell you exactly how much it cost because it was a birthday present. (Yes I asked for a propeller for my birthday.) But I do know it was purchased on Ebay. Sorry I can't give you more info.
dajutster 3 years ago
was i being rude? i was just stating that you don't have to use big words etc to be smart.and just curious, why would torque matter? isnt it with speed that you should be more concerned about?
FieldMarhsall 3 years ago
No, the speed is important but it is not the decisive factor affecting the machining precision. Torque is dependent on the rotational force applied and the length of the lever arm. My prop has much more mass than yours and is much, much longer. This requires more torque to make it do 1600 RPMs. It is that extra torque that amplifies the effects of an alignment error. Sensenich, the manufacturer of the propeller can confirm that for you; they did for me.
dajutster 3 years ago
regardless speed will have a more adverse effect on the prop than the torque to turn it.
FieldMarhsall 3 years ago
and i dont get the "precise equipment". a lathe, drillpress, and a steel blank. and there is your flange.
FieldMarhsall 3 years ago
When you are spinning it at 1600 RPMs, you had better be precise to the 1,000th of an inch or you're generating several newtons of off-axis force. That would eventually rip the propeller off the shaft or worse: the entire engine. If you tried your 'method' you would wind up dead. I don't say things without reason.
dajutster 3 years ago
Dude, what are you talking about? I run a 20 HP engine on a hovercraft with 1/8 clearance and there is no issue with "off-axis" force. I appreciate what you've done, but you don't do yourself any favors by trying to seem more knowledgeable than you are.
jmanjohns 2 years ago
I am not trying to be pretentious, or cocky, or "seem more knowledgeable than I am" and I honestly don't know why you think so. All I am saying is that for my application I needed to machine my flange precisely. This is both based on my calculations and the guidelines of the propeller manufacturer. I would imagine that you are using a pre-made flange that is already CNC machined to precise specs. I made mine myself and I wanted to minimize any chances of error.
dajutster 2 years ago
I uploaded my flange designs JustinAyers(dot)com/images/flange.jpg
I'd like to see you measure 1.0625" with your lathe and drillpress.
dajutster 3 years ago
lol you must really think you are smart. i will post a vid in a week or two of my "lathe" and "drill press". but you really think that .0005" off will matter? i got an r/c plane, and im pretty dam sure the prop isn't that accurate, and it spins faster than 1600 rpm.
FieldMarhsall 3 years ago
you don't need college credentials or classes to be smart kid
FieldMarhsall 3 years ago
I don't think I'm nearly as smart as you think you are...
I do not just "think," I KNOW that it must machined be that precisely - it can be proven with very simple physical formulas. In fact, I had an in-depth conversation about it with a college professor/engineer who is an expert in this field and would be happy to back me up. I can share his email address with you if you would like to discuss this with someone of some authority.
dajutster 3 years ago
Also, your r/c plane's engine operates with a mere fraction of the torque of my 2 HP engine and the propeller/flange is much smaller and lighter. Of course it doesn't have to be as precise. And as to your "you don't need college credentials or classes to be smart kid" comment, that is exactly what I meant by a "crude, useless comment." Keep posting garbage and I WILL delete it. I'll be happy to have a genuine discussion with you, but not if you continue to be so rude.
dajutster 3 years ago
that's what you got for almost 900 bucks?
FieldMarhsall 3 years ago
Yes, that's correct. Is that a surprise?
dajutster 3 years ago
Yes, that's correct. It is a surprise. You got a job or did mommy and daddy pay for it? i just couldnt believe you spent that much for it. there isnt much there. i mean, yea, you finish with some green flames? im not trying to be a dick, i just didnt think you would spend that much for about nothing. MAYBE if you bought everything brand new. and shit if you spent that much, i woulda made it look a lot nicer. but then again i do a lot of projects myself, not requiring other peoples work hours
FieldMarhsall 3 years ago
My parents payed for the majority of it, and I am very grateful that they did. For somebody who "does lots of projects" I am surprised that you underestimate the cost. There are multiple gasoline engines, an airplane propeller, custom CNC machining, and a heck of a lot of structural implements to make it safe and efficient. When you build a nicer hovercraft for less money then you can criticize me all you want. Until then, save your useless, crude remarks - they are helping no one.
dajutster 3 years ago
CNC machining? Which parts?
jmanjohns 2 years ago
Where did you get the fan you used on the back?
Fuelaenir 3 years ago
Ebay. It's a Sensenich 29" diameter, 22" pitch wooden airplane propeller. Mounting hardware is not on the market so I had to custom CNC-machine a flange from steel stock to mount it on a 2HP small engine (also from Ebay). Unless you have access to VERY precise machining facilities, I DO NOT recommend this method. Try to find a propeller which already has mounting hardware included. Please let me know what you come up with.
dajutster 3 years ago
hey, do you think two 31cc blowers @ 425CFM each can support a 4x5 foot platform at around 250 lbs? I'm currently also making a large-format hovercraft
cavalier777 3 years ago
Yes. I could get mine hovering with only one blower of similar size. Do your best to seal off any air leakage from the skirt. You can sprinkle some flour on the base of the hovercraft and run it to get a good sense of where any leaks might be. Be sure to buy plenty of duct tape! I recommend the system I came up with for securing the skirt- it's a few comments down from this one and very airtight. I wish you the best of luck! Post some video when you're finished; I'd love to see your work.
dajutster 3 years ago
Dude, that's so cool. Did you tried it on water? Well you should :)
ParaglidingManiac 4 years ago
No I have not - it's not powerful enough yet. If I ever upgrade the lift engine to a ducted fan (like in the back) or add another leaf blower I'll give it a shot. For now, I'd rather stay dry :-)
dajutster 4 years ago
Im having trouble with the skirt and my hovercraft wont stay stable. yours looks pretty stable. how did you make it?
PDJ11 4 years ago
The skirt is a PVC-reinforced canvas dropcloth bolted to the bottom of the base using a rounded plastic gutter cover. There are reinforced holes around the perimeter of the gutter cover. The edges of the skirt are sandwiched between adhesive weather stripping and 1/2" wooden molding strips screwed to the top of the base. Then they're taped down with duct tape. It's my own design and VERY airtight. Try varying the size and shape of the skirt; it can make a big difference in stability. Good luck!
dajutster 4 years ago
That was awesome dajutser. Congratulations on a great design. It looks like you were just like us (although a little older) in that you just wanted to figure out how do it as much as to have it when you got done. The end product is killer. Thanks, too, for checking ours out. Are you going to do another?
chapman55k 4 years ago
No, I'm not going to make another one but I do hope to make some major improvements to this design. I'm just so busy! Some day I will, but for now it will sit in the basement :)
dajutster 4 years ago
The steering on this thing looks really crappy. On the hovercraft I am building now I am using a thrust vectoring system that I found on the internet. Just google "hovercraft vector" and you can see how much better this is compared to flaps.
PDJ11 4 years ago
Homestly, it's not all that bad. The lift system is the crappy one :) The thrust vectoring you mention is interesting; the real advantage is the braking. Thanks for the tip and post some video of your finished hovercraft!
dajutster 4 years ago
On my hovercraft I am using a smaller 31cc engine and an 18 inch prop but the engine is modified to run at 7000 rpm so I should get plenty of thrust. my lift engine is 2 leaf bloweres that each move 400 cfm so I'll have plenty of lift too.
Also, about the thrust vectoring.
If you use this system there is no need for throttling the thrust engine.
PDJ11 4 years ago
looks cool, but a bit slow, don't know how it would handle over water though.
More speed, and better controls might make it even better, nice job though.
spider2021 4 years ago
Thanks! It was primarily made just to prove to myself that I could do it and the end of the school year put an abrupt end to my project. You are entirely right in everything you said, and it all stems from using a cheap leaf-blower as the lift engine. If I replaced it with a ducted propeller it would greatly boost the performance and I'm confident it would work well on water. I need the money and the time... Maybe some day!
dajutster 4 years ago
Oh also - you said that the contols could be improved. What did you have in mind? You would be surprised how effective the steering system is. Granted, the propeller's engine is near impossible to throttle. I need to add some form of reduction belt system to get more out of it.
dajutster 4 years ago
wow thats really cool ! so in like 10 or 20 years do you think is will be well like for real ? and you'll be a millionaire with this idea lol i looks like so much fun does it still work ? i hope so cuz i want a ride lol :D tell Leah hi for me ttyl - Amelia
ameliaseacamp 4 years ago