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Oct 26, 2020, 10:22 AM
Registered User
On my previous Elf which had a crash, I was using a small amount of down elevator and right rudder for a right-hand launch. For some reason this Elf is behaving a little different.

In any case Greg, what does your momentary switch do? Also what's the right way to find the settings for the three position switch? I would assume only thermal and cruise for the Elf although it can go relatively fast.

-A

Quote:
Originally Posted by glidermang
AstrohamFlyer:

I only have the one session on mine, and I fully expect to make many changes over the next several weeks as I get used to the airplane.

Once I got some confidence doing a full-turn launch, I started working hard on the flight trim. I was able to use a momentary switch to launch with the elevator in a position that allowed a straight-ahead climb. As the airplane slowed at the top, and the nose started to drop, I released the switch and went to a trim setting that gave a good, straight glide.

I anticipate going to a 3-position switch, just as with my F3K ships, for speed/Cruise/Thermal, and use the momentary for up-elevator at launch. Not sure when that will be - there is a winter storm watch out for hereabouts this evening, through Tuesday night. Yeah! Snow! We are in a terrible dry, and need all the moisture we can get.

Yours, Greg
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Oct 27, 2020, 09:41 AM
Registered User
AstroHamFlyer:

Sorry it took so long to see your qyestinon.

First of all, I am a late-comer to this thread, and have not yet reviewed all the previous posts. I am sure there is lots of great information on the really-truly good way to set up one of these cute little airplanes.

I currently have one (1) session flying my own Elf, so there is a lot of exploration I have to do to find out if I'm getting the best out of mine. Right at this moment, I am sitting at my desk with a cup of hot chocolate, watching the snow come down.

As it is set up now, I use a momentary switch to put the airplane into the elevator trim setting that gives a straight glide, no matter how fast it flies. There is NO tendency to pitch up as speed increases, as is usual for most airplanes. When I release the momentary switch, the trim reverts to best glide speed, and the airplane is hands-off-stable. I launch with a bit of up-throw, and the airplane climbs straight ahead as long as the switch is held. As the airplane slows near the top, it will start to pitch down, and the trick is to release the switch before it stalls, and maybe push over a bit into the glide.

Having spent the snow time yesterday thinking about it, I will set up a 3-positin switch exactly as I do for an F3K airplane: Speed-Cruise-Thermal settings, with forward-for-faster. I will then use the momentary switch to use the elevator to pitch up on launch, exactly as I do for a normal, F3K airplane. I can then throw level, for a more efficient launch.

It may seem like a lot of trouble for a "toy", but launching in a speed mode gave me maybe thirty percent more launch height on Saturday. Launching in a trim setting for good glide blew off a lot of the launch energy in turning flight, that often ended in a stall.

Is that clear? Too much?

Who has posted earlier, that knows better? I'm sure my approach is neither original nor the best approach.

Yours, Greg
Oct 27, 2020, 04:26 PM
Registered User
Lufo's Avatar
Post 2004 to 2010 covers this slightly. You can use a tiny, tiny bit of up elevator for launch on a preset. I used about a 0,5 ( half mm ) of up on a spring loaded switch and at the top of the launch I simply released the toggle and let the horizontal stab go to neutral. I also had a slight mix of right rudder on the toggle. Honestly that was the only preset that I used.

The ELF is pitch sensitive and it takes very, very little horizontal stab travel to effect a change. Using too much up on launch and the ELF will arc behind you and nose into the ground....usually breaking the boom.

Searching this thread using the word "launch" bring up a number of results, some not relevant.
Oct 27, 2020, 06:53 PM
Registered User
Lufo:

Thanks!

Greg
Oct 28, 2020, 11:12 PM
Registered User
I got a chance to fly mine today: late in the day, fading sun shining on grass emerging from the snow. But, variable soft breezes and soft, low-level lift.

I made no changes from my first session, but thoroughly enjoyed the airplane. Reaching out over the school buildings yielded some lift - so did heading towards the sun-facing bluff. I may have had a single, 2-minute flight, and certainly several 1-minute flights. Launch is satisfactory, but staying in the lift seemed (afterwards) to be problematic. I finally concluded the airplane is still too sensitive in pitch, and I was killing the soft lift with too many pitch excursions.

Solution: I can reduce elevator authority still more (restrict travel or use exponential), or I can use a 3-position switch for mode and the momentary switch for launch, like Lufo describes. The third position would be "Thermal", and simply be a bit more up elevator trim to hold the little airplane in a banked turn. Rudder control is fine: kit-supplied horn, about twice as long as the servo horn; push rod going to middle hole on the short servo horn supplied by Dymond.

I'm still thinking... Shhh! It's a painful process for me.

Yours, Greg
Oct 29, 2020, 07:19 AM
Registered User
Neil Stainton's Avatar
I don't have any launch switch or setting. I launch using exactly the same trim as cruise. The Elf arcs up and I apply full down at the top to level it off. I do restrict elevator movement to about 50% throw - just enough throw to avoid a stall at the top.

Neil
Oct 31, 2020, 11:23 AM
Registered User
Quote:
Originally Posted by Lufo
The ELF is pitch sensitive and it takes very, very little horizontal stab travel to effect a change. Using too much up on launch and the ELF will arc behind you ...
Quote:
Originally Posted by glidermang
... I finally concluded the airplane is still too sensitive in pitch, and I was killing the soft lift with too many pitch excursions.
Solution: I can reduce elevator authority still more (restrict travel or use exponential)...

Completely agree; I clearly see changes of flight behaviour with hardly any visible changes on elevator throws…

In order to get the best resolution possible, I drilled an additional hole (3.5mm from centre) into the servo horn of the D47. Much better now, but I still have to restrict travel electronically to get to my presently preferred elevator throws of 6mm up and 7mm down…

Initially I programmed flight modes but often ended up just using one or two clicks of the trim button to change from one “flight mode” to the other, if ever necessary.

Needless to say, any trim correction changes the launch behaviour of the ELF. You want the ELF to climb straight (speed mode) right after launch. Only then a tiny little bit of up elevator on a momentary switch for a fraction of a second may help to give it the right angle…

Martin
Last edited by small talk; Oct 31, 2020 at 11:53 AM.
Oct 31, 2020, 11:53 AM
Registered User

3D printable nose cone coming soon.


Elf new 3D printable nose cone almost done. I should be able get it done in a few days. STL file will be put on Thingiverse.
Oct 31, 2020, 12:24 PM
Registered User

Nose Cone


Cain't hardly wait. Now I will be able to color coordinate my nose cone with my wing covering. AND it might be possible to jiggle the code to make a cone slightly larger up front to accommodate a 2 s 240 mah battery more easily than is possible with the OEM cone. The internet truly makes for possibilities that I would not have had the imagination to even dream of two decades ago.
Oct 31, 2020, 06:03 PM
Registered User
Lufo's Avatar
Quote:
Originally Posted by miniellipse
Elf new 3D printable nose cone almost done. I should be able get it done in a few days. STL file will be put on Thingiverse.
Nice looking nose cone ... is it a strict replica or did you change dimensions?
Oct 31, 2020, 07:03 PM
Registered User
Almost strict replica. Main change is that it starts getting narrower toward the front further forward so my batteries fit. The difference is slight. The aft end is flat and does not have that triangle part like my original. I might figure out how to do that but not right now.
Oct 31, 2020, 07:15 PM
Afflicted with DDD
Soarhead00's Avatar
Just curious. I have an Elf Pro EL. Plenty of room in the nose since all the gear except the motor and small ESC are behind the cone.
Question:
1. Are the Pro and standard Elf nose cones basically the same shape at least as far as the mating ring on the fuselage? I'd like to cut off some of the Pro nose so I could move the motor (i.e. weight) farther back to get the CG further aft. I'm carrying 2 grams on the rudder to get my CG around 70 mm. I'd like to push it back closer to 75 mm without adding more tail weight.
2. Miniellipse, would you be able to publish the CAD file so it could be modified for the Elf Pro EL nose?
3. separate topic: is the Standard Elf wing the same as the Pro-EL wing? Yes, I know the standard wing has a peg.

TIA
Bob
Nov 01, 2020, 07:08 PM
Registered User
Quote:
Originally Posted by miniellipse
Elf new 3D printable nose cone almost done. I should be able get it done in a few days. STL file will be put on Thingiverse.
I'm interested in this too. Thanks!
Nov 02, 2020, 01:35 AM
Registered User
Patience guys. Iím working on a customizable version for everyone. Iíve got bulges where I need a bit more room for servo arms and possibly the battery connector (big bulge) on top.
Nov 02, 2020, 08:30 AM
Registered User
Quote:
Originally Posted by miniellipse
Patience guys. Iím working on a customizable version for everyone. Iíve got bulges where I need a bit more room for servo arms and possibly the battery connector (big bulge) on top.
Oh take your time! Just think it's a cool thing to do.


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