Spaceclam

thank you and good luck!

aambrose

Wow! I'm somewhat speechless! I just read this entire thread and I can't believe there are people out there who actually are trying to build Draganflyers! Cool!

I bought a DF IV about 3 weeks ago and I'm having fun with it but I'm far from being an expert pilot. I've flown RC planes in the past but this is a different beast. One question I have not been able to find the answer to is what exactly is the material that the DF props are made from. The only thing the guys at RCToys.com will tell me is that it's a "foam composite". I'd like to know exactly what the material is and maybe try to make my own from the very same stuff. Also, in regards to the blades losing their effectiveness at higher RPM, would a stiffer material work? Maybe polycarbonate or something like that?

This is a very interesting!

Spaceclam

the blades may very well be foam composite becuase they are so flimsy and stuff. the draganflyer turns it's rotors at about 1k rpm so you should not have any problems with them loosing their effectiveness as that is what they were designed for. my model was turning out 3k and later 4.2k, and what happened was the blades would go into negative pitch and loose most of their lift. if you wanted to make a stiffer prop i would highly reccomend either polycarbonate or anti-shock abs plastic. G/F nylon is too heavy for this.

aambrose

There's no doubt the blades are a foam composite. That's a general term and I'm just trying to pinpoint the exact material. Do you think something like foam PVC ([link=http://www.tri-dee.com/sintra_plastic_pvc.htm]Sintra[/link]) would work? I'm just wondering if a stiffer material (polycarbonate) would do more damage to the gears/frame/rotor screws in the event of a crash. The blades on my DF IV seem to be just over 1mm in thickness (.046" is what I measured).

Thanks!

Spaceclam

i have those blades too. it sounds like they may be made of sintra or something similar as it sounded about right.in the event of a crash, yes the stiffer blades would do more damage. you would probably just strip a gear though. if you are not having problems with your df than by all means, leave it alone and use the stock blades.

aambrose

That's just it. I want to be able to make my own blades that are very near the same material as the stock blades. I just dont want to pay the $20-$30 for a full set. Also, if I could "perfect" the process, then hopefully I could help others out as well.

Thanks!

Pipefish

The material is exactly EXPANDED PVC 1mm. Don´t try another one.

Pipefish

I got a perfect method to make them... Hope to picture it. How can I publish it in the forum?

aambrose

I'm assuming that translates to the same thing as [link=http://www.tri-dee.com/sintra_plastic_pvc.htm]Sintra[/link] which is described as:

Sintra material is closed-cell, expanded plastic, high-density polyvinylchloride sheet. It is acid free and has minimal out gassing for Archival use. Sintra is a homogeneous material that allows the ease of cutting without regard for grain. At half the weight of solid PVC, Sintra may be stapled, nailed, riveted, glued, and ther****rmed.

Thanks for the information! Have you had success at flying your homemade rotors on your DF?

To post a picture, click "Upload Images!" below the message box when you're typing your message.

Thanks again! I'd love to see some pics!

Pipefish

Hey aambrose,
I think it´s absolutely the same material, yes. Just different names in different countries.
I think mine are better than the originals (don´t know why they lift more).

I´m looking for a partner to make a 3 blade one. What about huh?
I´ll Upload the pics ASAP, ok? Gimme a a maximum of 1 day, ok?

Best regards.

Spaceclam

pipefish, you want to stay with a two blade prop. see, the larger the prop diameter the larger your actual rotor disk is going to be. if you go 3 bladed you will have to go smaller which will increase your rotor disk loadking. very much like wing loading in planes

Pipefish

Even if I make them 20 to 25% smaller?

Spaceclam

if you mean a diameter 20-25% smaller, you are cutting your rotor disk area in half. do the math. that means twice the loading.

Pipefish

No way to 3 blades be better?

Spaceclam

they will provide more thrust but you will loose some of your control effectiveness. it may be light enough as it is that it wont matter, try it and see.

aambrose

I'm looking forward to seeing/learning how you are making your props. I've checked locally for Sintra (foam PVC) but no one carries it. I'll have to order some via the Internet.

Oh yeah, has anyone considered a monstrous gas/nitro version of a Draganflyer? Not sure how motor control would work but the thought of a large scale version with lots of lift and maneuverability would be cool!

Thanks again!

Spaceclam

it would but then you have the problem of not all motors running the same, tuning all four and stuff. it could be done i guess but it would be a royal pain. i would try but i dont have the cash[:'(] you would have to have four of those fuel injected engines that automacially adjusts the mixture to maintain the correct rpm for each motor and have a comparitor somehow regulate them and then have to couple each of the throttle linkages to the same stick with seperate trims and one master trim for all while also have an automatic override to keep the rpms the same and to coordinate the rpm differences for stick movements and keep them close together meanwhile trying to isolate your receiver from the four engines and all that electronic circuitry... YIKES! i think i will stick to electric for a little while

aambrose

I figured that would be the response!

Spaceclam

i am sorry if i ruined it. dont get me wrong i want to try it but man that would cost at least 2k!

aambrose

I didn't misunderstand you.....I just figured the response from anyone would be "aaaaaaaaahhhhh!!!!". I think it would be very cool to see a large scale gas model of it. So if anyone becomes that ambitious, then be sure to post it all here!

Pipefish

Hey aambrose, there goes the promised pics.
Best regards...

aambrose

Thanks for the pics!

First of all, how do you cut the "blanks"?

Second, what process do you use to shape them? I noticed you have them clamped to a pipe or something but do you heat them while they're clamped?

Thanks!

Pipefish

I cut them making a mold from this picture:

Print it (is the original size of the DF IV prop) in a A4 size sheet. Cut it and glue it in a 2 or 3 mm PVC (Sintra) sheet. Tha´s your "MATRIX"

With the Matrix you can now cut as many as you can in a 1mm sheet (here in Brasil the size of the sheet is 1,22 X 2,44 (meters)).

You noticed that I clamped them in an aluminum pipe (Size 50 here in Brasil) - 300 to 320 mm (little more than a blade) with inox "bracellets" (I use 5 bracellets per side of blade).

To heat it (deforming with your hands wil not make a uniform pitch) I use a Hobbico blower (45 sec for each side of the blade). Yes, heat it while clamped (total 90 sec).

Hey Tony, just experience how much angle you´ll use before clamping, ok?

Spaceclam

i will tell you what. i will start a charity and see how much people are willing to donate

bitrate

Hi guys,
I am currently in the process of building a feedback system capable of flying my draganflyer autonomously, so this has proved an interesting thread.
I am wondering if any of you guys have considered using brushless motors on your machines?