BillHarris

Adding the slat in front of the existing wing leading edge is a perfectly adequate way to do this. But the overall outline of the Frisch wing is so close to the outline of the wing + slat that the wing begs to be modified. The downside is that it will be a bit more "fragile" , ie, prone to damage in a flight mishap. I'm not 100.00% set on doing the slats that way, I may end up doing them as add-ons. The wings will be the last phase of construction: there is the exterior and interior detailing of the fuselage to do, I'm going to use scale-type hinges on the elevator and ailerons (Frisch specifies iron-on hinges and top-hinged) as well as scale corrugations and surface details on the rudder, elevator and wings. And all the time keeping an eye on the finished weight of the plane. Scale is good, but not if it flies like a brick.

Another thing I want to do is add a reinforcing former to the rear of the door opening for a possible rear float attachment point.

--Bill


PS--

Here are some slat references:

http://www.rcgroups.com/forums/showthread.php?t=622119

http://www.rcgroups.com/forums/showthread.php?t=637654

http://www.zenithair.com/stolch801/design-wing.html

http://www.rcuniverse.com/forum/m_98.../tm.htm#986347

http://www.rcuniverse.com/forum/m_40...y_slats/tm.htm

http://www.rcuniverse.com/forum/m_31...y_slats/tm.htm

RysiuM

My Feedback: (1)

Luxeon Rebel LED works very well for navigation ligts as well as beacon. They are visible even at noon at full sun. Here are some pictures from New Year Flying at Mather Aerospace Modelers.

1. Warming up the engine (it was about 32 degrees that morning)
2. Approach with flaps fully extended
3. Scale touch down
4. Taxi back.

BillHarris

Beautiful plane. Makes it all worth it, no? The active nav lights (ie, visibel in the sunlight) add a lot.

What supplier did you use for the Luxeon Rebel LEDs? SuperbrightLEDs http://www.superbrightleds.com/leds.htm has similar 1W LEDs. What are you using for the lens on the tail-top beacon? I though I've seen flashlights/signalling lights with a similar lens, but I've not found anything usable.

Mine was originally going to be built as a plain-jane, utiltarian aerotow plane, but I've decided to add many scale details; currently I'm working on the interior (instrument panel, seats, etc) and adding slats and all the corregations to the wing panels. The fuselage is reasonably detailed, but I'm adding rivets and panel lines based on sets of BobBanka photos I have.

I've started a thread on adding slats in the Aerodynamics Fourm: http://www.rcuniverse.com/forum/m_6833227/tm.htm

--Bill

RysiuM

My Feedback: (1)

The best I found is [link=http://www.philipslumileds.com/products/line.cfm?lineId=19]PHILIPS LUMILEDS[/link] site and when you expand particular LED type (color) there is a shopping cart that takes you to FUTURE ELECTRONICS Components Superstore. They have the best prices, and reasonable shipping (fast delivery). I buy my stuff over there.

The lens for the beacon is a cup from CA kicker spray bottle. . I painted it with red marker from the inside. Remember, that there are three LEDs in the lamp. Each LED covers 180 degrees with overlapping that makes the light the same brightness in each direction.

BillHarris

Good, ordering the LEDs directly from the "factory" can eliminate links in the supply chain. I'm still going to look into other sources while I'm at it. It's great having nav lights that look good in the daylight; I'll post that info in a new thread.

At Home Depot today I noticed that MagLight is offering a 3watt LED bulb replacement for their incandescent bulbed lights. Three watts is impressive, and the light is offered in "2cell" and "4cell" ratings, so it could be usable as a scale landing light.

I'll dig around for my adaption of the beacon lens...
--Bill

RysiuM

My Feedback: (1)

I got my landing lights from the same source - PHILIPS LUMILED. Two LUXEON I Star O (1W each) in series. They are quite visible and don't heat much (they are burried inside the leading edge so not much cooling there is available).

Remember, in flashlights usually the entire flashlight works as a radiator, so it is easy to take this 3W away from the LED chip. At junction temperature 120C the white LED makes ony 70% of it's nominal brightness. At the same temperature red LED makes only 20% of it's nominal brightness.

BillHarris

That's right, 3 watts is still 3 watts and no device is 100% efficient, so something needs to be done with the waste heat created. Let me look at Philips' application data, small heatsinks might be a good idea.

Now that I'm getting the engine thrust/cowl/etc done, I'm going to start working on the "cowl inlet louvers" (or whatever they are really called). http://forumrc.alexba.eu/ipw-web/bul...=asc&start=306

Interesting problem in topology. I'm going to make my version with the center hub about 3/4" to 1" farther out from the firewall than the outer hub , so it's actually going to be a flat cone. As far as I can tell from your "Alex" website, it is made of lite-ply and 1/32" plywood, with 24 vanes. I think that lite-ply inner and outer rings, with 12 trapezoidal spacers to fit between the vanes (it may be a nightmare to try to cut 1/32" slots in the ply rings, but with a cutting jig, it might be do-able). Vanes appear to be set at 45-30 degrees to the axis. Or so I think I understand it. I tried to translate the Polish text with an online translator, but the results were a bit quirky, to say the least. My local bookstore had two different dialects of Chinese, French and Spanish but nothing Polish.

--Bill


PS-- been meaning to ask, what is the meaning of the "AE" on the rudder of some Wilgas?
--b

RysiuM

My Feedback: (1)

It is made easier than it looks. Believe me. It took me one evening to get it done.
Vanes are made of 1/32 plywood (hard ply) cut with scizors. Rings are made of 1/2 lite-ply (two layers of 1/4 lite plly sandwiched together). For cutting I used jigsaw (this one):



Slots are cut by setting the table to 45 degree and run straight cuts - fast and easy. The saw width is exactly 1/32 so vanes fit tight. After assembly (dry) I painted everything with 20 minutes epoxy. Epoxy soaked into slots bonding rings with venes. At the same time the whole constraction became fuelproof. You can see it here glued (painted with epoxy) before final (white) painting.



Let me know, what you don't understand on AlexRc, I will be happy to wrtite it for you in my broken English (as far as I can)

BillHarris

Ah, I see. It certainly isn't that difficult to make. I don't have a jigsaw, but I can borrow the use of one.

--Bill



PS--
Yes, I will. I've seen some very interesting construction techniques on the plane in that thread!
--b

BillHarris

I got a MAGLite 3 watt LED upgrade module for evaluation, 4Cell (6V nominal) Part# 108-000-717 The LED chip is similar to the Lumeon K2, but I can't tell the manufacturer of the LED without disassembling the module. The LED module is cylindrical and 0.442" (11mm) in diameter, and is a replacement for Maglite's incandescent Krypton bulb. The cylindrical body of the module heats up immediately when power is applied, which means that the LED chip is well thermally-coupled to the body of the module, so the body can be easily attached to a heat sink for prolonged operation, if need be. I would imagine that a landing light would be switched ON-OFF by the flaps or retracts and not be run continuously during flight.

Here are the initial readings on this LED:

650mA @ 5.25V (4 NiCd cells, full charge) 3.4W
450mA @ 3.70V (4 NiCd cells, minimal charge) 1.6W

Although the cost a bit steep at $18, this module is a plug-and-play solution and also has an "Intelligent Energy Source Management" feature (whatever that is) to control the enery useage, so I think it is a good item. A replacement reflector for the Maglite is available for a couple of dollars.

I have no idea what the luminous flux is on this LED, but I have a Minolta incident photo light meter and I'll figure a way to measure the output of this LED. As a "WAG", I'm guessing 30-40 Lumens.

Bill

djderstine

What a beautiful airplane. I admire the fact that you scratch built your Wilga. My Dad had a few of the Frisch 1/4 and some of our flying buddies had the 1/3 scale 35/80 and 2000. I love these planes. Great towplanes too! Enjoy and thanks for the posting pictures of the build-up.

Cheers

BillHarris

A couple more data points for the R&D of the MAGLight landing light:

I painted a black spot (so that it could be read with an IR thermometer) on the shell of the lamp replacement module so that I could see what the temperatures were during operation. I also evaluated how well the LED chip was thermally coupled to the lamp shell. Just on a hunch, I also pointed the IR thermometer at the LED chip at the output end of the module, abd found that the "chip temperature" closely tracked the shell temp, confirming that the chip is well thermally-coupled to the shell. I have no idea what the temp of the heatsink pad on the back of the chip is.

The module, in "free air", took took about 2 minutes to reach a steady temperature, which was 160 degF for both the shell and the chip face. Not bad, but I'll work up some sort of heatsink for the module (I have a heatsink for a Feigao 1/2" brushless motor kicking around somewhere).

Small world. John Derstine is who got me hooked on the PZL Wilga back in the late '90s. Which is how long I've been working on this one (I think I'm still using construction tips I got from John on this plane). I'll agree, too, Rysiu's scratch build is impressive.

Bill

RysiuM

My Feedback: (1)

I took another video of my Wilga flying. You can easy see these lights even it was sunny day (over 100F that evening). Video on youtube [link=http://www.youtube.com/watch?v=BRLr6Pj6Y2A]http://www.youtube.com/watch?v=BRLr6Pj6Y2A[/link]

BillHarris

Very good. Those Lumeon LED nav-lights are quite properly bright in the full sun. I've not noticed wingtip or bottom white strobe lights on the Wilga photos that I've downloaded on the Web, but they do look like an impressive addition to the nav lights. Since this plane is going to be _my_ custom Wilga and not a faithful scale replica of any one full-size plane, I'll add the extra strobes.

I like the light controller circuit that you have described and I may play around with it a bit, but I'm also going to evaluate the Dimension Engineering DELight controller: http://www.dimensionengineering.com/...ontroller.html .

I'm looking forward to completing this build, but I'm afraid that I'm starting to get back into having to buy expensive components on the final phase, such as a custom dual-cannister exhaust and large-scale servos and avionics. No big deal, but I retired a couple of years ago and need to watch nickels-and-dimes in today's wacky economy.

I'll finish soon enough...

Bill

jasec70

Hi, do you still have the assembly instructions to the icare wilga 35....