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Author Topic: Show us your P-30's  (Read 61785 times)
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betocastrucci
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« Reply #725 on: August 31, 2013, 05:36:36 PM »

I use the same altimeter, but in my P30 with a 50 mAh 1 cell lipo (big for it), total weight 4.9g (altimeter + batt + cables + conectors). I carry an old netbook to flying field Cool but I liked this interface to android, looking for it.
Today I was trimming my new Saturno V4, also lda = lots of drag airfoil Cheesy , with 1/16" (much thinner than normal) x 6 loops (53 cm motor length). I wounded 1000 turns for the flight in the graph, the maximum with this motor is 1400. Got some help from hot air. Tomorrow I'll wind it to maximum.
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Tmat
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« Reply #726 on: August 31, 2013, 06:00:06 PM »

For the contest geeks, the temp/time graphing is a good thing to have, and the gizmo IS physically smaller than the Eagle T.  The extra cost of the interface (GREAT addition) might be a big minus point.  Is it also in the HK lineup?
It's not in the HK line-up. For non contest geeks why bother at all?? For sport flying who cares how high you are getting? Spend your money on something else.
But it is only $17.16 for the Bluetooth adapter. So it's not really very expensive.
I bought it from here: http://www.himodel.com/FPV_Telemetry/Bluetooth_Module_for_FD-Altimeter_Altitude_Data_Logger.html

Tmat
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« Reply #727 on: August 31, 2013, 06:15:47 PM »

We have a 150 meter "ceiling" in our area is the main reason I'm in the market for such a gizmo.  I don't have telemetry on my radio and a stand-alone tele system costs almost as much as my DSX-11 cost.  I'd like to get a visual relation for my planes at altitude, and a unit that is small and light enough for the 30"+ FF models is icing on the cake.

I AM interested in how high I get (my planes, that is Roll Eyes)...
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« Reply #728 on: August 31, 2013, 09:40:36 PM »

MID390 airfoil is 7% thick and 3% camber. Camber seems low, but for P30 Re is probably about right.
Plotted it out and attached the drawing below.

Should need a turbulator to perform best in the glide, or a rough upper surface finish.
Certainly will be "low drag".


Tmat
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DerekMc
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« Reply #729 on: August 31, 2013, 10:24:01 PM »

Some of my rocketry buddies have very small and light recording altimeters. I will see if I can chase down the specs. For them.
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« Reply #730 on: August 31, 2013, 11:24:26 PM »

There is a very small Polish altimeter that the rocketry guys use here Derek. I have one, but again it needs a laptop to download the data.
This is the one I have: http://www.adrel.com.pl/altimeter.html

Tmat
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DerekMc
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« Reply #731 on: August 31, 2013, 11:29:37 PM »

Tony. That's one of them. I'll check with my altimeter guru friend about the others.
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Derek
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« Reply #732 on: August 31, 2013, 11:56:22 PM »

Fly Dream make a Bluetooth adapter for the HK altimeter that allows your to download the data to an Android phone or tablet device. That's what I plan to try next myself. Don't feel like lugging a laptop or netbook to the field either Pete!

If I want to plot the data on field, I use the Altitude Analysis software on my Palm handheld (unpublished version under construction adds support to FD-A). Then again, most of the time I´m too busy flying, it is just cool afterwards to see how the flights went.

Tony, please be aware that if the FD Android software is made by the same team as the PC software, it is - errrr - not quite perfect. At least the PC version does not take temperature into account (the logger measures it, the software plots it, but does not account for it when calculating the altitudes!). Temperature affects the readings in two ways. First it accounts the signal you get from the pressure sensor, and the sensors typically automatically deal with that. But in addition, the dependence of air pressure on altitude also varies with temperature, and if this is not compensated for, you get several meters of error (up to 10m per 100 meter when it is freezing) for your altitude readings. Needless to say, the Altitude Analysis and my Excel macro which I use to calculate altitude graph from the data I import to PC take the temperature into account... :-)
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« Reply #733 on: September 01, 2013, 10:33:14 AM »

Good points Tapio. Thanks.


Tony
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« Reply #734 on: September 02, 2013, 11:49:55 PM »

Here's my TitanK2, adapted from a Bruce Hannah design and replacing TitanK1 which was lost due to DT operator error.  (Yeah, stupid me.)

Airplane flew great right off the board, with just a bit of downthrust added.  I'm now fine tuning but haven't got up to full torque yet.  I think I'll be removing some of the right thrust, and possibly a tiny bit of incidence.  There are incidence adjustment screws for both the wing and the stab.

I'm going to try and post some video from today a bit later.

--Bill
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DerekMc
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« Reply #735 on: September 03, 2013, 12:01:11 AM »

Very nice Bill! Looks like you have a winner there.
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Derek
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« Reply #736 on: September 03, 2013, 12:37:14 AM »

MID390 airfoil is 7% thick and 3% camber. Camber seems low, but for P30 Re is probably about right.
Plotted it out and attached the drawing below.

Should need a turbulator to perform best in the glide, or a rough upper surface finish.
Certainly will be "low drag".

Mid-309. Yes, it is low camber, but seems to work ok. The P-30 has such low wing loading, that not much camber is needed. Also, the first session without a turbulator went ok, albeit a bit under-elevated. I then added a zigzag tape to 50-60%, and now it glides fine. Maybe a bit faster than conventional ships, but measured sinking rate is in the same ball park. In my latest fly session there was some turbulence as the evening breeze came in, but the model was stalling ever so gently, and about to settle again, no serious/violent stall.

 
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Tapio Linkosalo
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« Reply #737 on: September 03, 2013, 02:07:25 AM »

Bill, Titan looks like an interesting model. Semi-symmetrical airfoil and PGI trim? Should have spectacular power burst!
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« Reply #738 on: September 03, 2013, 06:13:04 PM »

Derek, thanks for the nice comment.

Tapio, thanks also. the airfoil isn't really what I would consider semi-symettrical, although I suppose it really is with the Phillips entry and otherwise nearly flat bottom.  The Phillips is probably a bit excessive near the wing root, and exaggerated by the picture.  This is only the second plane I've built from scratch, TitanK1 being the first.

The airfoil is RSG-29 (8.66% thickness, 4.33% camber) at the root tapering to RSG-82 (7.58% thickness, 3.79% camber) at the tip.  This was the closest match I found in Profili to Bruce's airfoil shown on the plan.

I am attempting to use PGI trim as the basis, although since I am doing this on my own and know of PGI only through these forums and internet, it is not pure PGI.  The original Titan design had a pylon, didn't use PGI, and used a shorter heavier motor.)  I think the plane does have a pretty sprightly climb for a long motor run P-30, but I don't have a lot to compare to and as I said I haven't gotten to full torque with this one yet.  Motor run for TitanK1 was about 1:40.  Motor is six strands of 3/32 (2.4 mm), lightly braided.

--Bill
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FF Bruce
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« Reply #739 on: September 03, 2013, 08:55:06 PM »

Very nice Bill,looking forward to see it go in a couple weeks
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didierlouis
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« Reply #740 on: September 10, 2013, 12:51:10 PM »

Tapio,
I appreciate your search for a better flying P30. (and in general your contributions are very value added ; many thanks).
In the P30 class the constraints due to the prop and to the small dimensions force us to look for directions unknown in F1B or G! It is good for our mind!
My first P30 when returning to modeling 4 years ago was an Ikara PeeWee; unfortunately I broke all what could be broken: balsa tube, wings, nose...
I decided to test high tech building with my P30 Addict 2: (relatively) high  A/R wings with an LDA captured in FFQ, MID 102 (see first pictures).
The climb was good but glide a disaster!
These same wings proved to be much more effective on my first F1K where the engine runs for 2 mn!
After testing a model built by Serge Millet, I derived from his design the P30 Addict 3: large area wings and an airfoil quite thick with little undercamber.
It glides beautifully and climbs quite high if not fast.
It was flown at the last Coupe d'Hiver in Viabon (winter conditions and a lot of wind) and would have won if not being hidden to the timekeeper by the hangar at the last flight.
A sketch is attached. Let me find a picture to be posted later.
You can also see on the wings picture  that we share the construction method.
My conclusion is that with the drag induced by the propeller on gliding, we have better to select  a slow gliding airfoil, a good surface (thanks to carbon!) and a reasonably fast climb.
With a 40g limit, I prefer save on the mechanism which could control the burst (and loose a little of altitude) and add surface.
Take care.
Didier
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Tapio Linkosalo
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« Reply #741 on: September 17, 2013, 01:45:08 PM »


It's not in the HK line-up. For non contest geeks why bother at all?? For sport flying who cares how high you are getting? Spend your money on something else.
But it is only $17.16 for the Bluetooth adapter. So it's not really very expensive.
I bought it from here: http://www.himodel.com/FPV_Telemetry/Bluetooth_Module_for_FD-Altimeter_Altitude_Data_Logger.html



I managed to get one BT adapter from Himodel, after I placed the order, the next morning it was "discontinued" (which I suppose is "out of stock", as I think this BT device is just a new one and will be more widely available when the factory produces more units...)

Really bad instructions, just says "install the software to your Android device" (yeah, how, so far I have only installed applications from Google Shop, and even trying to download the software from FD-A web page to my mobile fails....).

But! I have already built the support of FD-A to my Palm software, and also for trial had set up the software to support serial-over-bluetooth (and tested that with RAM3 logger). So, I thought I had the needed components... Powered up the BT dongle, paired it with Palm, went to my logging software where I chose BT port instead of copper serial, pressed "upload data", and.... data started to load! Voila!

(the pic shows logger to the right underneath the Palm, then the BT dongle and battery to the left. The log is a pathetic flight on P-30)
 
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didierlouis
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« Reply #742 on: September 26, 2013, 12:05:40 PM »

To complete my previous post, find  enclosed below a picture of the full model.
Didierlouis
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« Reply #743 on: September 26, 2013, 12:57:20 PM »

Didier

I hope that photo wasn't taken in Beaujolais at the end of November Shocked

Peter
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« Reply #744 on: September 26, 2013, 07:12:10 PM »

Hi Peter
Coupe d'hiver des Alpes du Sud, Sisteron, this winter.
Take care
Didier
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Tapio Linkosalo
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« Reply #745 on: September 27, 2013, 01:28:25 AM »

We had a contest here in Finland the past Sunday; there my best climb with the LDA was 70 meters. However, the air was boyant, in the glide the model was coming down, but more slowly than normal. Then again, in light lift my old, conventional model also climbed almost 70 meters...

Throughout the day the model seemed quite sensitive to rudder trim. A bit too much to the left, and in the initial burst the model would roll to the left. Reduce the left rudder, and now the model banked to the right when VIT triggered and climbed more slowly until torque burned down. It seems that banked high-speed turn was due to glide cedalage coming in too early, so that the model could benefit from 2-stage VIT. But would that be then too complex? I just wonder if I should try to build the model for PGI trim, would that made the climb more straightforward to trim? Then again, I do not like PGI that much (at least on F1B)...
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Tmat
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« Reply #746 on: September 27, 2013, 11:57:37 AM »

Maybe your rudder is a bit big Tapio?

Tmat
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Tapio Linkosalo
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« Reply #747 on: November 05, 2013, 02:26:51 AM »

The rudder is only 5 to 7 mm wide, so quite narrow. I think the sensitivity is also/mostly due to the high initial speed in the power burst. Low drag on the wing, VIT enabling straight initial climb, and motor wound to high torque means much higher initial speed at ballistic trim. Also the model shows the typical feature of nose up/down trim coupling to sideways move (too little decalage -> model turns left, and vice versa).

To another subject: the motor tubes shows on my models were laminated by company "Kultasiivet", but when this moved to Estonia the mandrels were lost in the move. So, as I attended "open evening school for adults" and class "techical work" there this autumn, I got the opportunity to use a metal lathe. There I turned my very own mandrel for P-30 fuselages. After several evenings of first turning the mandrel and then filing and sandons the surface smooth, I molded the first test tube out of glassfibre last night. Glass is good, as you can easily follow the release while it progresses from the thick end to the thin. I'm glad to report that despite the mandrel surface seems quite scratched, actually the file marks are shallow and do not feel if you glide your fingernail over them, and the glass tube released easily off the mandrel. So next thing is to laminate some tubes from kevlar and/or carbon.  This tube is 24mm diameter at the thicker end, so thicketr than e.g. Burdov tubes, but this means that I can use a shorter motor-to-peg -distance (without problems of motor bunching) and have less inertia in the pitch direction. The glass tube is less than 13 grams (100g/m2 front section and 50g/m2 rear), so I suppose with kevlar/carbon you could squeeze it weight closer to 10 grams.
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OZPAF
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« Reply #748 on: November 06, 2013, 05:43:58 PM »

That looks interesting Tapio. I'm curious as to how you release the moulded tube . Do you use inner wraps of plastic and perhaps vaseline to ensure release?
It also looks like you may have wrapped the outside of the glass with tape or similar.
Nice work anyway.
John
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Tapio Linkosalo
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« Reply #749 on: November 07, 2013, 05:57:27 AM »

The release agent is carnauba wax. I use Simoniz car wax in the yellow tin, but "official" mold wax is the same stuff. Add some 5 layers polishing inbetween, so the laminate does not stick onto the mold. Another important feature is that the mold is slightly conical (the motor tube part tapers from 24mm diameter to 22mm), and there are absolutely no grooves in the mold, where the laminate could stick into. The scratches in the previous pictures seem coarse, but actually they are not, if you slide your fingernail over them, you can barely notice them. But with the surface smooth ( I first used a file to even out all the marks from the lathe cutter, then moved from coarser sandpaper to finer, finishing with #800), the tube does not catch, but can be tapped off the mold.

The method of release is such that I mold a "lump" (a ring of thicker material) to the thick end of the tube. Once the tube has cured, I slip a piece of tubing over the thick end of mandrel so that the tube leans against the lump. The tap the tube (in practice fall the whole mandrel-laminate-tube a few cm against concrete floor) to the tubing, so that the slight shock is delivered to the thicker laminate ring and the laminated tube. This tries to push the laminate off the mandrel, and the linear shock probably ever so slightly expands the laminate, releasing it off the mandrel. In practice you can see (from glass laminate) how every tap looses 5 to 10cm of the laminate off the mandrel, until after some 10 taps the mandrel drops off from within the tube. Then you just saw the thicker ring off the laminate (and put it aside, as it can be recycled for the next laminate!)

I do not think that vaseline or plastic sheet would work, as for a good tubing the lamination needs to be made against a solid surface. Here the waxed steel works good. The kevlar cloth is wetter and wrapped tightly against the mandrel, then pulled tight by wrapping with a tape (used computer data tape); this pushes the laminate tight against the mandrel and squeezes off all extra epoxy. If there was plastic or vaseline against the mandrel, it would just twist around while the tape is pulled, and the cloth would wrinkle this way and that.

I made the first "real" tube yesterday. Motor tube 90g/m2 russian kevlar, tailboom 60g/m2 kevlar, with 3 layers of 100g/m2 glass cloth to reinforce the peg and nose. 430mm motortube and 260mm tailboom, weight 11.5 grams. As strong as my old ones, so good for use.     
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