Sci-Fi Cylinder Pusher - Should I Attempt Such an Undertaking?

[smithhayward]

OK! so it's 9:10pm here, but I really want to start looking at this. Going to try to create something that resembles what we're talking about out of cardboard. Initially my design was going to involve an approx. 9" cylinder, but I'm thinking that just in case I need more power I'm going to make it 13" so that I can use my Park 480 with a 12x6 propeller. I may start by prototyping it with my 935kvs that run their included 10x4.7 props. Anyway, going to go make an airfoil with variable thickness with the same chord (I'm still getting used to all of the aviation terminology). Get the top of the cylinder to have the thicker part of the foil.

I'll try to take some pictures and videos of test throws...

~Smith

UPDATE: 11:02pm

OK, so I made the cylinder out of cardboard. The corrugation made it easy to crease around the circumference. I used some scrap foam to make the tail (fin and stabilizer) and connected them to the cylinder using our trusty FT BBQ skewers. I haven't thrown it yet, I kind of want to do it outside in the grass so it doesn't break every throw.

For some reason I can't get the pictures to be right-side-up... Ugh!

Next step, add some contour to the cylinder to make it more airfoil-y. Haha!

 

[ProfessorFate]

Hi Smith!!

Oh, that looked like what I did 1st flight on a stryker yrs ago, then figured out flying wings have to reflex the elevons up about like 10-15 degrees, and this, is neutral.

My 1st thought was generally a THICK NACA 18 symmetrical airfoil all the way around the cylinder ( symm ... same on bottom as on top

This aircraft, it's just an artist's idea of a fictional "cool looking" aircraft; by no means really a good aeronautical design having any kind of built in stability, and its going to want to roll even in fwd flight like a pool cue rolls on a table, so what if the cue was heavy on the bottom and some force pulled it up from the lighter top end? You would want to be sure and get the flat bottom of the Clark facing down to get this right ( around from 10 to 2 o'clock position )

then it I thought, why not have a lifting foil on top to try and hold the top of the aircraft up.... see pic in other post


This is the lifting airfoil for the top:



This is the fat symmetrical foil for the bottom to grab the air:


I really think this will work, it just won't have the best flight capability. But it is a very interesting challenge! Yah I think you are right when saying maybe you put a larger prop in there .... one thing I just thought of tho is that a larger prop, while being more efficient will also produce more torque roll forces, it will want to rotate the aircraft, so maybe if your cylinder is about 12" you might put a smaller prop in there to spin at a hi rpm, maybe a gws 9x5 if this is light or if you have a larger motor and things get heavy, a 100gram 1400kv motor and an apc 9x6e prop





remember we often set the angle on our firewalls with the motors to offset this problem with 3 degrees right and 2 or 3 degrees down



see on that 11.1 volt prop test on Cobra motor, apc 9x6e ( that's the prop Nerdnic used/tested the Suppo 1400kv motor with ) produced about 65oz of thrust ... I compared similar motors with the 9x6 prop to guess at what thrust you could get from the Suppo and Suppos often have 100kv higher that what is listed... if it spins a 9x6 with ease, good. A large prop will want to roll the craft over and a smaller prop ... less roll tendency

also with this roll tendency ---- prop choice not just the size: I think a thinner lighter prop might produce less torque force, like maybe a thin gws 9x5dd or some other thin light 9x6 or 9x7 like a graupner thin electric series 9x6 or 9x7, being inside a duct, you probably won't break many props, they won't be exposed anywhere

with this shape/ aircraft planform, you don't really have much of anything at all to counter for torque roll, maybe setting the thrust angle in the rear could help but just think of it ... all there is, the 3 stabs n ctrl surfaces in the back, the nose with the canards may not help much at all





I think to put an idea together short, simple, what if you scale this to make a cylinder 12 to 14" diameter, Clarks @ top, NACAs @ bottom, and use that Suppo 1400kv motor and some light thin electric 9x6 prop with a 3 cell battery, figuring you already have some 3s 2200s, maybe try apc 9x6e or 9x7 first since they are so common/ easy to find, later if you want to help the roll problem more if there is a hobby shop near, look at the thinner graupner props ( pricey, I know ). In your testing you may see so much roll tendency, it may just not work, but, I don't really know.

If we started out stacking it up as much in our favor as possible, it could with as much hi lift at the top, being carefull and sure to put all weight in the bottom as low as possible


Maybe you just try these ideas and whatever directions you have and see what happens, how it works

I have thought so much of this, after I finish the Savage Bobber, I kind of have a desire to play with this too.


Ohhhhhhhhhhhhhhh, where's the CG gonna beeeeeeeeeee

Now I think that cardboard chuck tester to figure out CG WITH the Clark airfoil at the top may be needed


But even without the foil, just a plain thin cylinder and the rest of the craft with its canards in front and rear stabs may be enough to help you find the right CG



Smith .... you can turn your pics right side up just in windows, right click and see the menu offers you options to rotate pictures

Leonard




Y'know... if you got a "BEEF" motor and gws 9x5ep prop layinaround you could just stick it on your cardboard tester along w/ radio n servos and see how this flies before investing w/ other materials


might want to test the cardboard chucker naked.... first, and get the CG figured out



"Well!..... I'ld like tuh see the Great Leslie try THAT one!"





Hey Smith

Do you have anything that you enjoy flying right now? Just thinking, if not, then you might want to build an FT Mustang, Spitfire, or Bushwacker, these would easily work with smaller cheaper motors you might already have in your collection, like that 1250kv 2217 "Beef" motor and a gws9x5dd w/ 3s batt

Feel like I should build a Spitfire or Mustang too, it's so little investment and looks great...been really slow to work with dtfb, plus I live n S Texas, it's hot and stuff made using hot glue may melt and I really like to always carry my plane n radio in my truck in case I want to fly. Nothing on my stryker will melt, it's foam & tape.

I have a stryker made fm the plane white foam blank and 1800kv motor w/ 6x4prop, but, I'm tired of stryker flying wings... not having the flight site in front of home depot may be the thing, it was on the top of a hill, I liked how it flew there... now they have a tire store on that nice grassy strip! On a 3s2200 I would get about 25min flights casual, floating around and chasing an occasional covy of birds

Did you/yall see on Youtube: Flite Test Spitfire flight and review -- Tjrosenberry

Looks real nice, has that mystique the quieter brushless electrics have that use 8x4 or 9x5 prop, warbird paint scheme

https://www.youtube.com/watch?v=sDKAVogLi7A

https://www.youtube.com/watch?v=gs0KE__lsL0

I like that cool blue overcast day he took the video on

See End Of The Road RCs Mustang and Fokker D7 biplane

https://www.youtube.com/watch?v=ZYg9v0VWOD8




Something you might want to do is get a Paint Shop program that works good for modifying or drawing pictures, I make these up as stat/spec/proj review sheets, everything at a glance on one pg, what it looks like, how big, WS, AUW, Pwr Sys details, who made it. TJ has a 4 video series on how he made his Fokker

These are great idea sheets, you make up or collect a bunch, and when ever you want to build a plane, browse thru these as well as other stuff

Found those motor n prop test sheets are quite handy, I know my Cobra 2820/10/1170kv will give me 57.5oz thrust w/ an apc10x6e on a 3s lipo, know your pwr system to have an idea of what your build weight could be, this is the motor I will use on the Savage Bobber which should come in at about 2#--- thrust=3.5#, planning on some good 3d hover capability



Haven't put these motors to the test flying them yet, BUT, everything about their look, feel, heft, size of shaft, choice for good quality noodle wire, all makes me think they are some of the best motors available aside from the really expensive top shelf stuff made in Germany

This one in particular just looks perfect for a lot of 2 to 3.5# models with its rpm range on 3s either apc 10x6 or 10x7e or one of those really cool looking black Master Airscrew 10x6x3 three blade props ...

For its size n kv, the Io is 1.6Amps, pretty efficient, but, you should look at something similar in Scorpion motors, their hi efficiency is interesting.

This Scorpion looks great for driving an apc 12x6e on 4s for almost 100oz thrust 6.25# of thrust, but, I did not miss it, $125

When I get back to work I might get this and some 4s bats for bigger plane projects


See Nerdnics Mustang thread, he likes the Tacon Bigfoot 10, I think that might be a real good choice for a motor too

Might get the Tacon motor @ MotionRC.com

Look at that P-39 video Nerdnic has on this page
http://forum.flitetest.com/showthread.php?9193-FT-Mustang-Build-Log&p=232589#post232589





Well maybe your planning fpv or something w/ versa wing?

 

[smithhayward]

Hey Professor!

OK, so you drop a bomb of a post on me, you get one back... LMAO!!!!

~Smith

Oh, that looked like what I did 1st flight on a stryker yrs ago, then figured out flying wings have to reflex the elevons up about like 10-15 degrees, and this, is neutral. Plus I don't think the motor/prop combo is powerful enough - see below...

Yeah, I probably didn't have ENOUGH elevon-up for neutral... next time I'll get that set up better.

My 1st thought was generally a THICK NACA 18 symmetrical airfoil all the way around the cylinder ( symm ... same on bottom as on top

No, I'm going to put some spars around the circumference inside and outside, ensuring that at the top of the cylinder it's wider at the top and more symmetrical at the bottom. I mean, how thick should this be? The depth of the cylinder is only 7" and the diameter is 8.75". I was thinking going 1/4" up on the top airfoil and 1/4 up and down on the bottom. Then I was going to try to cover it with something thin and light (paper?) I don't know what they're called, but I could also cut the airfoil cross section pieces out of foam and use them on the top and bottom then wrap it in packing tape for the flight surface. THOUGHTS ON THAT? (I can't promise that I won't try something before you answer LOL!)

This aircraft, it's just an artist's idea of a fictional "cool looking" aircraft; by no means really a good aeronautical design having any kind of built in stability, and its going to want to roll even in fwd flight like a pool cue rolls on a table, so what if the cue was heavy on the bottom and some force pulled it up from the lighter top end? You would want to be sure and get the flat bottom of the Clark facing down to get this right ( around from 10 to 2 o'clock position )

then it I thought, why not have a lifting foil on top to try and hold the top of the aircraft up.... see pic in other post

Yes, I think that will be necessary - though the canards will be below the center line of the craft so that might help with top/bottom weight distribution. We shall see.

I really think this will work, it just won't have the best flight capability. But it is a very interesting challenge! Yah I think you are right when saying maybe you put a larger prop in there .... one thing I just thought of tho is that a larger prop, while being more efficient will also produce more torque roll forces, it will want to rotate the aircraft, so maybe if your cylinder is about 12" you might put a smaller prop in there to spin at a hi rpm, maybe a gws 9x5 if this is light or if you have a larger motor and things get heavy, a 100gram 1400kv motor and an apc 9x6e prop

remember we often set the angle on our firewalls with the motors to offset this problem with 3 degrees right and 2 or 3 degrees down

Here's what I have, I'm trying not to buy any more stuff (other than maybe a gyro)...

3 - 2200kv suppos 5x5;6x4 (I got some 5x3x3-blades to try out on these - maybe for a mini guinea pig)

1 - 1380kv Leopard that calls for a 8x4.3 (I'm running an 8x4.7 on it for my Storch now, but it can come off, it's just mounted to the power pod. It's rated at 170W. I probably need one of these for my Versa too.

1 - 1020kv E-Flite Park 480 - capable of turning a 10x7 through 12x6 with max power = 275W

2 - 935kv designed for multi-rotors that came with 1045 props, supposedly MAX power is 200W, so let's call it 150W continuous (EDIT: it's 130W) without burning her out; This is what I put on the Versa Wing - I think with the smaller 0847 prop that I installed it just wasn't enough power for the Versa.

I have plenty of ESC's for them all, a few 30-amp MAX (that say 30A on them - I hate that) plus 1 Turnigy 30A (Max in the 40's) and 2 Turnigy 40A (Max 55A) so I'm all set as far as powertrain goes I think.

Do you think the 935kvs will work for this craft with their full-size 1047 props? The motors are relatively light though (58g with mount) while the 1020kv Park 480 is 91g.

with this shape/ aircraft planform, you don't really have much of anything at all to counter for torque roll, maybe setting the thrust angle in the rear could help but just think of it ... all there is, the 3 stabs n ctrl surfaces in the back, the nose with the canards may not help much at all

Might there be a way to vector some of the thrust out the cylinder and off to one side (thinking 3 ducts) pushing opposite the roll tendency to counter any roll. I will play with thrust vector though, but should it be DOWN? I was thinking UP which might also help keep the nose up a bit more. Am I thinking in the right way AT ALL??? HAHAHA!

I think to put an idea together short, simple, what if you scale this to make a cylinder 12 to 14" diameter, Clarks @ top, NACAs @ bottom, and use that Suppo 1400kv motor and some light thin electric 9x6 prop with a 3 cell battery, figuring you already have some 3s 2200s, maybe try apc 9x6e or 9x7 first since they are so common/ easy to find, later if you want to help the roll problem more if there is a hobby shop near, look at the thinner graupner props ( pricey, I know ). In your testing you may see so much roll tendency, it may just not work, but, I don't really know.

Yeah, I'm thinking about making it at least 12" across, I'll start mocking it up in DTFB soon. Do you think it would be possible to make a solid-straight wing using the FT method then notch is out and roll it up using the same method they do for dihedral (sp?) I would try to notch it every 1.5" or so in order to keep the semi-cylindrical shape. The circumference of a 14" cylinder is going to be 0.02" shy of 44", so 44". I'll have to join some foam sheets together to get that. I think going bigger with foam is beneficial because you'll increase area with minimal weight increase. I'm thinking @ 14" across that I'll shoot for 10-11" deep with the prop line being somewhere around the rear 1.5" mark.

Yes, I have (4) 2200mAh 25C lipos, also (1) 1200mAh 30C and (3) 850mAh 35Cs I haven't used the 850's yet, was planning on trying to build a relatively light cruiser (from scratch, my own Frankenstein design out of crap I have laying around.

Maybe you just try these ideas and whatever directions you have and see what happens, how it works

I have thought so much of this, after I finish the Savage Bobber, I kind of have a desire to play with this too.

BY ALL MEANS TRY TOO!!! LET'S FAIL AND LEARN TOGETHER!!!!

Ohhhhhhhhhhhhhhh, where's the CG gonna beeeeeeeeeee

Now I think that cardboard chuck tester to figure out CG WITH the Clark airfoil at the top may be needed

But even without the foil, just a plain thin cylinder and the rest of the craft with its canards in front and rear stabs may be enough to help you find the right CG

I'm wondering if I can make the base of the canards a little over-scale, I might be able to fit my 850mAh batteries in there. What if I could do that and wire them in parallel for a net 1700mAh distributed left/right equally but also lying somewhere around 20-30% vertical mark for bottom weight... didn't want to make it that complicated, but I think I knew that it would be going into this. Don't be surprised if I just give up one day

Yes, I'm going to test the chuck version with the airfoils...

Y'know... if you got a "BEEF" motor and gws 9x5ep prop layinaround you could just stick it on your cardboard tester along w/ radio n servos and see how this flies before investing w/ other materials

might want to test the cardboard chucker naked.... first, and get the CG figured out

Yeah, I'll chuck this thing around once I get a fuselage and canards mocked up. I have some of the "great stuff" foam that I sprayed into a giant ball that I can use to carve out some parts. Like I said, I love to play with possible new materials and get ideas from them.

Do you have anything that you enjoy flying right now? Just thinking, if not, then you might want to build an FT Mustang, Spitfire, or Bushwacker, these would easily work with smaller cheaper motors you might already have in your collection, like that 1250kv 2217 "Beef" motor and a gws9x5dd w/ 3s batt

Did you/yall see on Youtube: Flite Test Spitfire flight and review -- Tjrosenberry

Yeah, I just watched it. I'll probably build something like that someday. My time will be consumed by THIS project of course, plus I have my Storch i'm trying to get off the ground and the Versa that I crashed yesterday will need to be repaired or simply rebuilt. It's possible that my first crash loosened my prop causing the instability and ultimately the second "fantastic" crash.

Something you might want to do is get a Paint Shop program that works good for modifying or drawing pictures, I make these up as stat/spec/proj review sheets, everything at a glance on one pg, what it looks like, how big, WS, AUW, Pwr Sys details, who made it. TJ has a 4 video series on how he made his Fokker

Yeah, I have Photoshop and I'm pretty good with it... as for rotating my pictures, I tried rotating them. They look normal on my PC, I took them right-side-up (with my iPhone) and I even tried uploading them when they looked upside down on my PC and they still appeared the same on the forum.

Found those motor n prop test sheets are quite handy, I know my Cobra 2820/10/1170kv will give me 57.5oz thrust w/ an apc10x6e on a 3s lipo, know your pwr system to have an idea of what your build weight could be, this is the motor I will use on the Savage Bobber which should come in at about 2#--- thrust=3.5#, planning on some good 3d hover capability

I need to see if I can find some test sheets for the motors that I have and keep them handy. I have a "Design" binder that I keep a pad of graph paper in so I can jot notes and sketches in when the ideas hit.

This Scorpion looks great for driving an apc 12x6e on 4s for almost 100oz thrust 6.25# of thrust, but, I did not miss it, $125

WOW, that's expensive, we'll have to hold off on those for a little while. The girlfriend is already freaking out about all the crap I've amassed in the past month, Oops!

Well maybe your planning fpv or something w/ versa wing?

I won't do FPV until I'm a little more experienced. Plus I don't have anyone that I know (yet) who flies so I wouldn't have a spotter (like I know I should). Like I always do, I may get the equipment so I have it when I'm ready, but we'll see. Let's just get a plane in the air consistently and actually have it come down in one piece.

Keep the ideas flowing - you're helping my thought process immensely. Someday I'll get that online collaboration thing setup somewhere on the Interwebs, then we can share sketches and design ideas in a way other than asynchronous dialog.

 

[smithhayward]

Sorry if a little, OK, a lot, off topic...

I forgot to mention that I will TRY to make my prototype fully functional but only if I think it's sturdy enough to withstand the weight of a battery. I'll probably wait until I build the full-scale DTFB version to give that a go, for now I need to focus on designing how the fuselage with the electronics in it gets mounted to the cylinder and the rear control surfaces.

I'm also considering embedding two wheels in the bottom of the cylinder airfoil and adding a single gear stalk at the front. I think the real test of this thing's ability to fly will be to take off from the ground at speed.


OK... I just picked up the following from Amazon for delivery Thursday... Yeah, I have a SERIOUS problem...

OrangeRX RX3S 3-Axis Flight Stabilizer w/DSM2 Compatible 6CH 2.4Ghz Receiver - I chose 6 channel in case we figure out we need some additional control capabilities - I have a DX6 Tx.

Thin ELEC Propeller 12x6E

Great Planes 8x6mm Power Flow Slo-Flyer Electric Propeller (2-Piece) - these are for the Versa

Electric Propeller,11 x 7E

So, the larger props can be turned by my Park 480 if need be. I honestly don't know what I was planning on building to take such a beefy motor when I bought it, so maybe it is destined for this build after all. If it's rated for 10x7 - 12x6 SHOULD an 11x7 work OK? I wonder if it would drive a Kracken - yeah, my girlfriend would break up with me if I build that monstrosity unless I made it modular and storable. Maybe the Kraken could make use of these (3.5" retractables) that I got:

 

[ProfessorFate]

Hi Smith ! !! !!!


This is what I'm currently building, makin it up as I go, hate it that it sounds cliche but, that's what it is

The Savage Bobber, my wood version, and I'm not a purist, so if I think the plan needs a change to make it fly better, then I change it

OK just B4 finding the CG, if there are any thoughts of changing the planform to make it fly better, then get that like you want it now, then make your cardboard tester like that, and next then.....is

One of the most critical things, this is a pusher with canards, you have to find out where your CG will be.

Take that cardboard thing you got and just put 2 quick dirty canards same scale size in front and maybe (?) that fuse mocked by anything, just make it about the same or make it about the size/proportion you want to fly, go out in the back yard with that, some tape and quarters or weights you can use for balance and chuck that thing without motors or batteries or radio gear, try to see what balance makes it fly in a straight path the best. I am thinkin maybe CG might be right at the Leading Edge of the cylinder. This would be valuable info you would get to know where to put your equipment

You know how with other models, paper, you put flaps and adjust how they fly by bending them up just the right amount so it makes them fly the longest, too hi adj and they just porpus up them stall down, then you kind of split the difference, adj a little up, not too much and the free-flight plane flies straight
this is the idea with the cardboard tester/chucker


I know for sure with the Bobber I am building, and don't have to figure or ask anybody, because this is a regular conventional shape, that my CG will be about 1/3 behind the leading edge of the wing, for sure. So in my planning and building, I just go straight ahead and plan the batt will be close the the LE, the Landing Gear will be at the LE or maybe .5 inch fwd of LE of wing ....

knowing where that CG is, is important so you know where to mount your servos and batt and gear



When you build a flying wing, and you want to find a guide for the initial CG estimation, there is a diagram, a kind of geometrical exercise to find the MAC, Mean Aerodynamic Center.

Well there are also formulas and help pages on finding good starting points for other types of aircraft too

You need an approximation of the MAC for a canard aircraft

OR just thro the thing and play with it till, like some experimental paper airplane, you get the CG then apply that to the real model you will put motor and gear in


"...... this tape will self destruct in 7 seconds...."

 

[smithhayward]

Sounds good to me. I mocked up the fuselage in foam board already. It's basically an octagonal tube for now. I'm actually trying to find something to use to make the canards now. Once I can figure that out then I can get them all connected and start chucking it around. I'm also going to have to devise a way to actually measure CoG on this thing (with it being so odd shaped).

We'll get there. I'm trying not to go TOO fast, otherwise I rush into things, things break, then I lose my drive. Slow and steady...

 

[ProfessorFate]

Hello Smith

You could simply take that thing you made and showed us in post 21 and put some canards on that with like a few skewars for each just make the canards pieces of cardboard


One thing I can see is that the weight of the canards or other components could be significant to deceive you about the CG or MAC necessary to make this work, now just for simple chuck-test I liked what I saw in post 21, just add your canards and find out what you need

Maybe just simple cardboard canards, each one on like 2 or 3 skewars, cut little flaps on the aft side of the canards like you would for a paper airplane

*****************************
*****************************

Hope deferred, makes the heart sick

You said you were still trying to get your Storch flying, and your Versa Wing is not working either... you really might want to set this harder project that will not pay back in spades, aside, and figure out the problems with your Storch and make it fly and enjoy it for a while in parks and nice places

The Storch is a conventional airframe, and you are attempting something here which I clearly know, will not give good flight performance, it's just that we got carried away with, hey... we can make this fly...see I hear what your saying, got to get more familiar with terminology and concepts about how these things work..... on and on etc. So maybe it might be better for you to figure out those things that keep the Storch and Versa Wing from working, this is harder and the rewards are not going to be ... much, and I really did not know about your own flight experience

I just got into re-winding motors, also on RCGroups, so I'm all primed with the formulas and concepts about how to make motors more efficient with my own re-wind, I did 4 so far and none of them have worked, I did however, find out my mistakes in winding the coils the wrong way, but have put that aside for a while to just go build something I know will fly and go to the park and have a ball with like I used to, it's really quite peaceful, maybe fly next to a beautiful golf course or something

Anyway, I'm not attempting anything that won't work good for sure, right now
My last project was the Morane Saulnier, made it too heavy, fiberglass, I did not thro it away, but have set it aside kind of like we do for hard problems, a tv I cannot fix, set it aside, go on to another one that I can fix and return to this one a little later after a few good times and victories


Remember just look back at TJs Mustang, cool huh? ( really like that magnetic top hatch he has ), I am kind of tired myself of not having anything to fly and I don't really want to try anything at the moment that I know would not work, so this is why I went for the FT Bushwacker and transitioned into the Savage Bobber ( my wood version ) it's conventional and I just know it will work, the results are very predictable

I have made big mistakes before, a fiberglass flying wing 36 inches looked really cool, more like a flying brick, right after that failure, I wanted something that would fly, no troubles
Hope deferred, makes the heart sick.

if i start something else at the same time, i think i would make the FT Spitfire or Mustang out of DTFB, I should probably do that ( they are already designed ), and go slow and careful with the Bobber, it's like a work of art and there are a bunch of things to figure out, I go a little slow sometimes, think about certain problems like now, where to put the El and Rudder servos, under the wing around the Leading Edge or bottom deck fwd of battery, see then it leads to a question of how to route the control rods, and I was re-examining the area of the Rudder and comparing SB to FT BW area of rudder and stab, the BW has a bit more, might increase mine just a little bit, next examine the horz stab areas and compare, might make mine just what the FT BW are. Now if I go make the FT Spitfire, there is nothing to figure out, sure it would work, Peter or Josh has already optimized this for good flight.

You mentioned you might just give up

Well at the end if you make this and it just barely flies and you don't have your Storch or Versa Wing flying, well that might be kind of discouraging

Just seriously this is how I would feel if I were you.

Leonard

 

[smithhayward]

I started looking at cutting out the forms for the wing sections of the cylinder and I was surprised that 15% of the 7" is over an inch of thickness. I don't know if this is overkill, but I'm willing to try anything. I may try to design it so that I can test it with the larger (thicker) airfoil first, take video and notes on performance and then shave them down and continue until we have a good balance of lift and looks.

Trying to do this tonight - I'm also considering designing a Douglass Devastator that will use the new landing gear I got and ideas for that are interfering significantly.

 

[smithhayward]

Thanks Professor! So while my Versa is damaged, I have plans to rebuild it probably with the blunt nose mod. My Storch is ready for Maiden #2, just have to find the morning to go take her up. So, yes, I do have these other things going on, but they have their own timeline and I am giving them their due. I will continue to mess with this as time permits and I'll post pictures or videos of tests that I perform, but it'll be a long term project.

 

[ProfessorFate]

Jack Lemmon in The Great Race, Professor Fate


Originally Push The Button Max! from The Great Race

https://www.youtube.com/watch?v=R3Igz5SfBCE


Push the Button Max! orig fm Henry Mancini and The Great Race
https://www.youtube.com/watch?v=RtoD6FiCmFQ


Push the Button Max!
an interesting variation from a Mancini tribute disc called "Shots in the Dark" This track is by Del Noah & the Mt. Ararat Finks

https://www.youtube.com/watch?v=b4rAUt1jNZY


"Up you idiot, Up!...."


Foiled Again!
https://www.youtube.com/watch?v=7vE3Z5-6ROc
I want to build this Curtis Pusher from The Great Race, have you ever seen this?

The pusher with the ailerons inboard and no canard.




Leonard

 

[ProfessorFate]

How to do round wing spars?

Just thought of this....ever see those light weight circle clamps used for sewing, you would find in the fabric dept?????

Ever see how some carpenters make really cool stuff curving the wood, they boil it in water and then clamp it around a form to hold the shape, while it is soft and it hardens?

Now another way to make a circular wing spar, glue a bunch of thin strips of wood around a circular form, ok, take a 5 gal bucket as your form, get some thin wood 1/16" thin? cut strips to some width say 5/8 - 6/8" and glue 4 or 5 layers together making sure to stagger the breaks in different places

you can make a top wing spar and a bottom wing spar, the inside spar dia = 14", the outside spar is the height of the airfoil, like if the airfoil height is 1.25 inches then you have to make the dia that much bigger
you have to draw a picture of the wing, put in figures and get the height of the airfoils or your wings thickness


good grief that's just the wing spar, you also have to have a Leading Edge and a Trailing Edge to the wing, doh!



Maybe you have already found yet another idea to make the wing spars, there is a drawing I made of a really cool curved Manta Ray like craft I wanted to build 10 yrs ago, would have had to do something like this



Two more really good ideas:

1: Hobby Lobby has these really cheap 36" dowel sticks I'm building my Savage Bobber with, the 1/8 and 3/16" dowels are only 29cents each, you could take a bunch of these, throw them a hot bathtub of water and soak them for a few hours or all day, fasten them to a circular form to dry..... those would make everything LE,TE,Spars

2: More costly but, take something like Dave Brown's carbon fiber strip, sold in .5"x6 foot lengths for about $5, wrap this around your 5 gal bucket and then epoxy it, it should hold the shape pretty good, but, I have never really used this stuff, bought some to run along the top and bottom of my 10foot glider wing ( not built yet but I got the stuff to do it ) This stuff I would wrap and just overlap the edges about 1/8....so Circumference = 2 x pie x dia OR pie * dia that's about 6.28, so for a 1foot circle to make just one rotation takes pie or 3.14 feet, 2 wraps = 6.28 feet


well maybe the cheaper idea with the dowels might really be a winner for this project
You know you would not have to have much precision with this initially, you just wrap the wet dowels around the form and let them dry for a day, clamped in the circle form, well you could buy 10 of them for $2.90 and turn them into circles, the 3/16 dowels are sure looking good on my Bobber! and "...they're cheap as beans, mate!"

I am really liking these Hobby Lobby dowels for a const material



Ever look at xjet videos or rcmodelreviews channel on youtube? I think this is Jeff Simpson.


"...all I wanted was sausage biscuit!"

 

[smithhayward]

Progress! WITH PICTURES!!!

Yes, I have packs of dowels at my disposal, but I've gone ahead and just cut them out of foam. What do you think I should cover them with to form the actual airfoil? I can use packing tape (maybe a few layers), or Fiberglass Tape, I have card stock I can use (manila folders).

Here are some pictures of what the fuselage looks like before I attach it (after I finish the wing)..

BTW, we're going to call the cylinder the WING from this point forward, I hate typing cylinder.

Anyway... Pictures... Feast your eyes...

The right angle is how it will connect to the inside of the wing and position slightly below the centerline.



This iteration of the fuselage is probably a little longer than the final one will be. I'm also leaving the nose open (which I may be able to do in the final build (help with cooling and general aerodynamics)



I just made up my own profile for the airfoil. These are going on the top of the wing between 10 and 2. I have smaller ones that I made that will go top and bottom of the surface from about 4 to 8. I figure 8-10 and 2-4 can be without any contour - AGREE?



And this is what it looks like now on my kitchen counter...

 

[smithhayward]

Been watching some videos on building a thrust measurement test bed. I had tried in the past but didn't build it sturdy enough. I think I have a new design that I want to use. I purchased a new motor and ESC (on their way) and I think once they come I'm going to run all of my motors and prop combinations through their paces and chart everything.

 

[ProfessorFate]

Hi Smith, Leonard

That cardboard tube looks so convenient for the flat bottomed lifting foils, now to get the symmetrical ones that grip the air but only produce incidental lift, you could put the lifting airfoils all around the outside and from 2 to 10 put those same half pieces on the inside so no Bernouli lift is produced, this lift is caused by a difference in pressures where the air running over the top of the foil has to go faster, making a low pressure ( vacume ) and then relatively, the bottom is a high pressure as the air just goes in a straight path, so the difference in pressures produces an upward force.

I wonder now, considering the resistance that would occur, by the diff foils, if they should both be equal thickness, maybe even the lifting airfoil, because of where it is positioned, if it were slightly thicker, the drag at the top would produce lift and also pull the front end of the craft up because of more drag at the top

There's going to be forces at work that should be equal, you should be thinking carefully about, the balance of resistance, if the foils on bottom are thicker, greater resistance would torque your nose down, being that there are fewer lifting airfoils at the top, OK 2 times lifting foil height plus thickness of cardboard, and consider making the lifting airfoil that goes on one side only, THAT thickness.

I was wondering about all the funny things a person could say about 3 foot dowels soaking in the bathtub!!! Doh!!!



Here's what I'm workin with, just put the servo shelf in place, see that gap in the middle there, that's at 33% plus and minus about 3/4", gonna put blind nuts n perpendicular plate there to bolt the wing down

Point is I know for sure where the CG will be so these other things can be put into place with confidence. Next is to start that nice looking tail

 

[smithhayward]

Thanks, Leonard!

Yes, we are totally on the same page on the thickness of the wing. I have full-height on the top and the spars I plan to put on the top and bottom of the bottom part of the wing are about 1/2 of the top ones. I think my brain just automatically thought about the thickness being a problem if it were different and there being too much drag on the bottom otherwise.

I still need to cut out the other spars then I can cover the wing and then attach the fuselage and start chucking. I'm considering creating some sort of launcher so that I don't have to rely on my arm for consistent chucks, but we'll see.

More to come soon.

*** SPECIAL ANNOUNCEMENT ***


I'm HOOKED!



I got my Storch in the air this morning. She flew beautifully, motor gives good power. Got about 6 minutes on a 2200mAh 3S at full throttle, but she cruises pretty well at only 40%. She has a little too much elevator even fully trimmed down all she wanted to do was climb; again, not a bad thing considering my novice status. I have a video that I shot plus on-craft footage so I just need to edit that together, hopefully today/tonight.

 

[ProfessorFate]

Hi Smith, you mentioned how fat the wing and we are thinking of aerodynamics, look at this Edge 540, see how fat the wing is, and hey it uses small motors like we have collections of, well I have these park 400-450s, this is a review page from RCGroups, these can also be found on RCUniverse and I like the product pgs on NitroModels too, they show what's in a model a certain size n weight, just kind of spec everything out for you, like what size motor/prop/batt did they drive that thing with....

This E-Flite Edge 540 auw is only 16oz WS is 35.5"

You can find product pgs on old Nitro Models of foam warbirds, the 1100mm and 1450mm (55 inch) they don't even sell anymore, these are usefull

Been thinking lately of buying motors for driving props w/ 4s n 12x6 for things that weigh 4 and 5#, this helps to see what you might do it with.


Now you have, think a bunch of small hi spd hi kv motors too, like 1800-2200kv to drive like 6x4props on 3s, I read over and really enjoyed an RCGroups thread on F4 dtfb builds, you could sometime build an F4 like this design in the thread and use your motors w/ 6x4 for this, forum started and design by:

F-4 des by Matti Huaviala 2200lipo 9x7sf parkjets.com 888:

View attachment F-4 des by Matti Huaviala 2200lipo 9x7sf parkjets.com 888.zip

build thread:

http://www.rcgroups.com/forums/showthread.php?t=297515

parkjets.com link to f-4

http://www.parkjets.com/f-4-phantom/

this is the name I have on my zipped file, I think where I reposted the design near end of that big thread, when somebody asked about it. There are a lot of interesting designs also at parkjets.com, jetset44 steve shumate contributes a lot of these on RCGroups and parkjets

I have a bunch of these 2200kv parkjet motors, and think i'll build one of these dtfb f-4s

I was looking for this f-4 thread and found this: 600 plans

http://www.rcgroups.com/forums/showthread.php?t=1333878&page=5

and this F22 Raptor Foam Board Scratchbuild with swappable power core:

http://www.rcgroups.com/forums/showthread.php?t=2514126

When they quit selling that last really nice stryker, the one Quiki Somenese designed ( spelled wrong ) that used the stronger park 480 2200kv motor that drives a 6x6prop, I bought 4 of these so I am set up to build some jets sometime in the future



Made a pic as a pusher





We gotta get ready, the Goa'uld are coming.

 

[ProfessorFate]

Smith! Glad you got your Storch flying, I like that warbird!

Sometime I have to build the Storch dtfb and paint it up warbird colors, already bought the paint for it
One thing good bout dtfb, no covering problem, just paint it, and it can look so good

Look at luft46 and other sites German planes, some paint schemes have the rudder yello and body various versions of green camo.... looks good. I also got yello paint for this too.

Yall flyin' these swapables could make your pods fm 1/8th lite-ply ( it's about 1gram/sq inch ), put 1/4" hard ply on nose along w/ more cooling holes and some Great Planes 6/32 blind nuts n hex head bolts, build in 3degR, 2deg down angle...this'll be how I make mine

Might build a lite-ply wood pod today

this is where I'm at w/ Savage Bobber:

 

[ProfessorFate]

Take a look at Nerdnics build techniques n pwr sys nnP-39!

If Nerdnic can fly dtfb at 120mph, there's got to be something really good about his construction ( double walls, aluminum wing spar, etc... ).

http://forum.flitetest.com/showthread.php?19204-nnP-39

I just started reading this thread, and did not know, performance n durability and this nnP-39 looks like something to build for sure, think I might like the lighter floaty system on this one that would give better duration.

Some motors I'm just thinking about: Nics #1 Tacon Bigfoot 10 1100kv for $28, Nic #2 Turnigy D3530/14 1100kv
http://www.hobbyking.com/hobbyking/..._Brushless_Outrunner_Motor_US_Warehouse_.html

Nics #3 Suppo 2814--6--1400kv Park480 for $23... this one could be good if you wanted to get a lot of thrust from a smaller prop APC 9x6


One I like for quality, better flight time Cobra 2820/10turn/1170kv for $43 from innov8tive.com use with APC 10x6 for 58oz thrust on 3s

Cobra Io @ 10v = 1.6A 10 Turn motor for 1170kv 10x6prop, Bigfoot Io @ 7.4v = 2.7A 5 Turns for 1100kv 10x10prop.

After studying motors, you can see that having an extremely low number of turns in the motor will make it use a lot of power. Just a thought for comparing motors you buy in the future. #turns and Io and kv.

 

[smithhayward]

Pictorial Update: Canards Installed; Ready for Chuck Tests!

All good inputs... Here's a pictorial update of the prototype. I'd say she's ready for some CHUCK TESTS!

At first I was planning on using paper towel tubes with spars for the canards...



Then I wanted to feed the canard airfoils through and I didn't like how much work it seemed to be so I ditched the tubes...





Ultimately I like it without the tubes for now. The final flying version should have them as tubes. I'm hoping to be able to make them adjustable (either pre-flight or in-flight)

Just hot glued them in this morning. I'm going to put a small dowel between the fuselage and the canards so they don't get too much force and break off during testing.






An initial measurement of CG shows that it's floating right around 40-45% from the leading edge. I'll chuck it around as-is for the first test and hopfully get some decent video to show the characteristics. Then I'll slowly add weight to the front and retest until I get the CG as far forward as about 20% from the leading edge.

Anyone have suggestions for my chuck tests? I wanted to figure out how to "launch" it other than just chucking it, but we'll see... Crossing my fingers that I don't destroy it.

Motor thrust tests are pending so I can figure out what motor/prop to put into this prototype to see what happens...

 

[tblake3]

Counter rotating props

I skimmed through the thread, I like where it is heading. I saw a comment about the craft not having much in relation to torque roll resistance from the prop. How about the possibility of counter-rotating props? You could adapt the "transmission" of a Sharper Image helicopter. The design may at least get you down the right path.

I have never designed an aircraft. My true flight time is limited to those Sharper Image indoor helicopters so I may completely off base in what is possible. Just thought I might share what popped into my head.