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Jun 27, 2005, 11:26 AM
Dismembered Member...
arx_n_sparx's Avatar
Thread OP

Free Plans for the Hydro Plane, Part 2


Continued from this thread: https://www.rcgroups.com/forums/showthread.php?t=380781
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Jun 27, 2005, 01:22 PM
Disco Shrew
Superweirdash's Avatar
Hi,

I know I'm a bit late to the discussion, but I've been reading through the various threads on the hydrofoam, and I haven't really gotten a good idea of the power system that is expected for a model like this.

I know other people have asked this same question in the main 2 threads, but I haven't seen any comprehensive answers, or any tailored to these plans.

If anybody has a recommendation for a motor/battery set up, I'd love to hear it.

Thanks,
Ash
Jun 27, 2005, 01:42 PM
Registered User
I believe this has been posted a couple of times, but here is what Mike & Ernest (the original designers) were using to make their video:

https://www.rcgroups.com/forums/show....php?p=3892929

https://www.rcgroups.com/forums/show....php?p=3893746
Jun 27, 2005, 02:19 PM
Figure Nine Champ
madsci_guy's Avatar
Quote:
Originally Posted by Skylar
Thicker wire doesn't make a motor run cooler!
It does indeed. Thicker wire has a lower DC resistance which translates directly into less "I squared R" heating in the coil, so with all other factors the same, thicker wire will result in a cooler running motor. It's not the only factor, but it is a contributing factor in how hot a motor runs.

-- Val
Jun 27, 2005, 02:28 PM
Launchpad McQuack
Prop-er's Avatar
It's always nice to have the basic info on the first page of a thread:

If you are new to this thread, plz have a look HERE first...

If you are building, check this post regularly, updates are here all the time, I will post updates at the bottom of this post.

DISCLAIMER: UNTRIED AND UNTESTED, YOU MIGHT ENCOUNTER LITTLE MISTAKES. PLEASE FIX 'M YOURSELF, AND NOTIFY ME WHAT YOU DID.

we got 5 Hydro planes flying!!!

So I guess it's experiMENTAL

PLANS HYDRO PLANE A4 TILED (A4=210x297mm)

And how to sort all the 21 pages you can see here

PLANS HYDRO PLANE A0 NON-TILED (A0=1189x841mm)

Alternative link: HERE

Autocad DWG-file: http://rapidshare.de/files/3381105/plans2.dwg.html

You will need one sheet of 3mm depron, 1250x800mm.
All pieces are 3mm. Add some carbon rod on places that need it.
https://www.rcgroups.com/forums/show...8&postcount=49

For your reference: the length of the fuselage (floats included) is 600mm (divide by 25,4 to get inches).



Expect an all up weight of around 7,5 OZ or 200 gram, using 3C 450mah Lipo's. You will need a 2 to 1 power/weight ratio to be able to take-off from water. (loads of drag)

Steering is done by three servo's. You use double elevons. Think of it as a biplane flying wing, then you get the idea. Use delta or V-tail mix. If it's not on your transmitter, buy a V-tail mixer (around $10,-) which connects between your servo's and receiver. Connect a servo arm with one of the lower elevons. Connect the lower elevons the the upper ones by carbon rods. Use shrink tube on the rods as a hinge. Check the pictures.

You need double rudder. Again, one servo to a rudder, then rudder to rudder.
Water turning is much improved using a water rudder. Look at the pictures to see how it can be done. It looks like a hurried after thought. Try to work out a neater solution.

Center of Gravity is about 60mm from front of wing. (not from front of floats...but you got that right, right?)

You have to protect the floats against asphalt abuse. You can use thin carbon sheet. Looks really nice, is very light. I don't have any CF sheet around, so I'm gonna try and use 25gr glasfiber cloth on the bottom of the floats. I'll use a polu-urethane laquer on the GF. An other alternative is very thin plywood, although you should check how it reacts in water first.

The only two things missing on the plan is the canopy and air duct. The canopy is not an easy part to make out of depron. I suggest you make it out of foam block. Cut to rough shape, sand it to perfection, hollow it to make it light. I let the air duct to your own fantasy. I'm sure it drags a lot, so don't overdo it. Here's a pic for reference:



AND THE RESULT LOOKS LIKE THIS:


You really should consider buying a kit from Mike, when they arrive. Mine is just a quick SPIN-off.

This thread inspired me to draw the above plan:

Hydro-Foam flying hydroplane... video and plans info

This plan is not to be associated with www.michaelconnally.com.

But, if he, and others who cooperated on their project hadn't given us enough information, this plan would not have been possible. You can show some respect, like I did, by donating through Pay-pal using paypal account: [email protected]
.

----------------------------------------------------------------------------------------------------

UPDATE 1: If you would like to tweak this design, go ahead. All parts of the original fit really well to each other. If you changed things, and it doesn't fit anymore, help yourself. You can download the DWG file HERE

UPDATE 2: It is necessary to make your floats watertight. You can try the following: after assembly and glueing of the floats, treat them with spackle, or fill any gaps with strings of depron and CA. Make 'm neat. Give it a good coat of laquer, use a light one, like poly-urethane used to coat stairs. Test your floats in the bath-tub before risking any racing on the lake !!!

UPDATE 3: It seems to be better to increase the elevons area. Try making them larger. This will result in better response when taking off from water.
If you already have the elevons ready on your hydro plane, just wait to see if you are satisfied with flying. Making 'm bigger is a small modification. Drawings are not to be updated. (for now, at least)

UPDATE 4: The Germans have two of these flying. They report that Centre of gravity is further to the front, 80mm from the front of the wing. (20%)
Problems so far are leaking floats and sensitive/twitchy flying, due to wrong COG. Will keep you posted, and hopefully we get a video.

UPDATE 5: Pjotrrr has one flying very succesfully. His findings are that the centre of gravity is at 60mm from the front of the wing. It takes of from grass and water and flies very nice.
Last edited by Prop-er; Jul 26, 2005 at 03:18 PM.
Jun 27, 2005, 02:53 PM
Registered User
Prop-er,

I tried printing the plans in the A4 format and I get some spacing of the plans between the top, middle, and bottom pates. The left to right are fine. Is this normal? I also tried using it in banner mode with similar results.

Thanks for the help and good job on the plans!
Chuck M.
Jun 27, 2005, 03:31 PM
Launchpad McQuack
Prop-er's Avatar
Mac,

1. you are sure you print them on A4 size paper settings (210x297mm)?
2. you are sure you've set scaling to 1:1, keep aspect ratio ?

I haven't heard this complaint before, and I think maybe hundred people have printed these plans.

Let me know if you can solve this problem.
Jun 27, 2005, 03:34 PM
Registered User
If anyone is interested, I believe this is the kit that Ernest used:

http://slofly.com/cart/product_info....products_id=76

With this wire:
http://slofly.com/cart/product_info....roducts_id=160

(I bought one and just finished building it... haven't tested it yet, hopefully it works.)

Also, to hold the splash guard (electronics cover on the bottom), it looks like Ernest used these magnets:
http://slofly.com/cart/product_info....roducts_id=205

I was playing with some of these magnets, and they are SUPER strong!
Jun 27, 2005, 04:20 PM
Registered User
Skylar's Avatar

Power Requirements


Quote:
Originally Posted by Superweirdash
......If anybody has a recommendation for a motor/battery set up, I'd love to hear it. Thanks, Ash
This is my understanding of the power requirements of this concept (based on flying various other similar sized models):
  1. The wing area limits the weight of the power system and ultimately the AUW (all up weight).
  2. With a model built from this free plan, one should aim at an AUW of 200 - 220g (250g max). That means: airframe, electronics, motor and battery!
  3. If vertical performance is required (and also for taking off from grass and water), a power to weight ratio of 2:1 (or close to it) is needed.
  4. Therefore, static thrust should be 400g - 500g, depending on the final AUW.
  5. Given the small wing area, the forward flying speed will be relatively high, which means that one should not only aim for adequate thrust, but also a high enough pitch speed.

Taking the above into account, I’d go for a power system that:
  1. Weighs max. 100g for motor, ESC and battery.
  2. Produces 400g – 500g thrust.
  3. Has a decent pitch speed, say 60km/h minimum.

Here’s a thought on pitch speed:
Case A: A 11x4.7 prop turning at 5,000 RPM gives approx. 470g thrust (which is enough), but only has a pitch speed of about 25km/h.
Case B: A 5x4.3 prop turning at 13,000 RPM has a pitch speed of approx. 60km/h (taking into account a reasonable slip factor), but only has 350g thrust.

Both of these draw approx. 7A from a 3S LiPo pack, but don’t be surprised if I choose the latter setup for my Hydro Plane.

I hope the above encourages some of you to think twice before mounting a heavy motor on the front of your new creation.

Christo
Jun 27, 2005, 04:27 PM
Registered User
Skylar's Avatar
Quote:
Originally Posted by madsci_guy
It does indeed. Thicker wire has a lower DC resistance which translates directly into less "I squared R" heating in the coil, so with all other factors the same, thicker wire will result in a cooler running motor. It's not the only factor, but it is a contributing factor in how hot a motor runs.
-- Val
I know what you're saying and you're right. Thicker wire (more cross sectional area) has a lower DC resistance, but with multiple strands of thinner wire, it's possible to pack the slots tighter and get even better results.

In retrospect, I think it's only a wording problem, but it sounded a bit misleading.

Christo
Jun 27, 2005, 04:43 PM
"Experienced-Crasher"
Demon-Leather's Avatar

Geee...


I almost missed the second part...
Jun 27, 2005, 04:55 PM
Experienced R/C Repairman
barnyardflyer's Avatar
Steelgtr,
Toward the end of the first thread, you asked "What battery?"
It was the Apogee 3s1p 830 mah.
I tried readings on a Thunder Power 3s1p 860 mah, and results were identical.
I just tried a GWS 7035 HD prop, and thrust dropped to 15 1/4 ozs on the Custom CDR SE, but I'm going to try it in the field later, weather permitting.
Jun 27, 2005, 05:52 PM
Still Screamin'!
rvincent's Avatar
This is not a motor building discussion so I don't want it to turn into one, but, Skylar is right. There is no way the specs given can produce the numbers given on only 5.3 amps draw. And with a 2500kv to boot. With 11t's of 24g wire and 12 magnet poles it would be no more than 1500kv and it couldn't spin the prop listed fast enough to generate 21oz's thrust on only 5.3amps. On 10-12 amps I could believe it, but no way on 5.3amps, no way. I am not saying anyone is lying, just the number won't add up. I build many special motors for Littlescreamers and have many myself that are very close, but at higher 8amps readings.

Just my 2 cents
Bob
Jun 27, 2005, 06:45 PM
Disco Shrew
Superweirdash's Avatar
First off, thanks tcable and Skylar. Skylar, you're post was extremeley informative. I have a lot to think about now.

But as far as printing out plans, is there a local place I can go? I had Kinko's print out a full scale plan (and laminate it) a while ago from a JPEG. However, they (or the image file, I'm not sure which) got the scale wrong, which ended the project close to halfway through the building process.

Is there any chance of the scale being a problem with a PDF file? I'm inclined to beleive that PDF's are designed with accuracy of dimensions in mind, and that they do not becomee easily misprinted, though that may not be true.
Any suggestions?

I've also noticed that the sources for Depron in the US stock only (surprise!) imperial dimensions for their sheets. So, no 1250x800 stock sheets. Is there a close combination of imperial sized sheets that would work? It looks like DepronUSA carries 13"x39" and 19"x27". Would either of those sheets, in any combination, give a desirable result?

Thanks for the help,
Ash

Thank
Jun 27, 2005, 07:02 PM
Experienced R/C Repairman
barnyardflyer's Avatar
Quote:
Originally Posted by rvincent
This is not a motor building discussion so I don't want it to turn into one, but, Skylar is right. There is no way the specs given can produce the numbers given on only 5.3 amps draw. And with a 2500kv to boot. With 11t's of 24g wire and 12 magnet poles it would be no more than 1500kv and it couldn't spin the prop listed fast enough to generate 21oz's thrust on only 5.3amps. On 10-12 amps I could believe it, but no way on 5.3amps, no way. I am not saying anyone is lying, just the number won't add up. I build many special motors for Littlescreamers and have many myself that are very close, but at higher 8amps readings.

Just my 2 cents
Bob
Your right, last night the 21 oz thrust was measured with the battery connected to the ESC. Then later, when I checked the requested amps, I did not recheck the thrust. I tested again tonight, and found out the 12" JST extension cable I made, was robbing power from the motor, and I could only see 15 oz of thrust at 5.3 amps. When I removed the extension, I was reading 9.78 amps at 18 oz of thrust. When I removed the ammeter completly, which has two JST wires at each end, both 6" long, I was back to 21 ozs of thrust.

I know JST connectors, and wires are small, but I was waiting for everyone to agree on the best connectors to use to save weight, before I change everything. So far, it looks like the Deans, but I was waiting for something possibly lighter, with wires already attached.
Last edited by barnyardflyer; Jun 27, 2005 at 07:13 PM.


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