fairings

[rahulchoudhary73]

Hi Martin,

what do you think about the B1 lancer fairings for the gull? there could be quite some lift generating storage space in it as well. wonder if one has come to oshkosh yet.

thanks,
rahul

[mkoxxy]

That would look cool! But it would come at a high price in weight, probably
more than could be offset by added lift. Mark chose the single wing with
the D-cell to get maximum lift at minimum weight. As much as I'd like to
have folding or removable wings (like the RV-12) (and early designs had
those), the strength / weight ratio of the single, straight wing is
essential to stay at or near Ultralight targets.

[ukey4917]

Hi Martin, When I am piloting my Gull (2000 & 20ft drooped ends & Rotax 503, 3 blade) I think lift off is about the same air speed flaps or no flaps & if the stick is back too far I get tail (wheel) touch. How would you describe the D-cell and straight wing flight feel? Gary

[earthstaraircraft]

Hi Gary
Use 2 notches of flaps, about 20 degrees, for short field take off.

And check your elevator cable tension. Tie the stick hard against the aft stop, so that it can not move, I have some one hold the stick. go to the trailing edge of the stabilizer and push down were the rib attached to the trailing edge with about 5# of force. The trailing edge should not move more than 1/2 in. And no movement is good. If your cables were to loose than the plane would be slow to rotate for take off.
Tail touch is ok.
Happy Flying
Mark

Sent from my iPhone

[rahulchoudhary73]

wonder what if the lancer like fairing was built into a single wing Dcell, that'd be lighter than a retrofit at least. wing stays detachable like now
rc

[ukey4917]

Mark, thanks for the reply on the short take off. I did check thatstabilator trailing edge with weight. I get some push down but maybe an inch.Cables seem tight. (I just removed re-installed stabilator and tightened up theI-bolt on the cross-tube for the stabilator (I thought it may have beenwallowed out but no evidence of that found.)

I have about 33-half turns on the jack screw for the anti-servotrim tab (I use half turns cause that is easy to count with marks on oppositesides of the knob.) Question: I have noticed on take off that if I have thetrim biased to the nose-up then I get a fairly steep climb (have to push stickforward). For short field take off, do you like the trim in the middle orbiased to nose up?
Gary

[earthstaraircraft]

I like the trim un biased.
Tighten your elevator cables and you will get your predictability back.
It is so loose right now that you are not getting full up when you are pulling back on the stick at rotation speeds.
Happy Flying
Mark

Sent from my iPhone

[blaswichk]

I’m on that one too. My plane had slop in the elevator that Mark helped me find at the our fly-in. We have a long paved runway, and I use no flaps, full power and pull back about 55-60 mph and launch upwards with a strong climb at 70-80 mph. Yes, fairings help. I’ve added speed and glide with mine, you just have to spend some precious time designing and building them. but the end result is more fun, bigger smile.

[mkoxxy]

Yeah, we talked about wing root fairings a while ago. Kess and others are
out for speed, whereas my flying is more Ultralight-like - low and slow. I
don't want anything obstructing my view.

I operate from a paved runway, too, and don't use flaps during takeoff
(unless I'm showing off). But I rotate at 40 mph and climb out at 50-60.
Different missions, different planes.

I would have to say, though, that I'd like to be able to set trim before
takeoff, not to bias anything, but to avoid surprises.

Martin

[ukey4917]

1st  theconfession: I removed the stabilator to inspect the I-bolt on right side due tosome play that could be observed by stabilator manual pressure (my hands on thestabilator while doing a simple inspection). (Once off and I found the nut viaa previously cut inspection hole in the underside I tightened it first and itbehaved like the other one that was still tight. Then I took the nut off to seeif the hole in the cross tube seemed wallowed out but nothing I could find. Inever did get the I-bolt removed from the hole in the tube (a bit of a mystery)but I put the nut (plastic insert) back after adding one very thin aircraftwasher in the existing stack of two.) Backtracking a bit, during disassembly,being ignorant of how the cables worked I pulled the pin from one clevis andthe cable spun around in the long tube and soon came to rest.(I then recognizedthe tensioning residing in those cables.)

 

Right after that I went to the control stick and undid the upperturnbuckle and like an amateur I screwed it all way until it popped out of thelast threads. Then I went to the stabilator and released the second clevis pin.(All the while basking in my ignorance of the second turnbuckle tensioning theother control cable.)

 

2nd the observation: after reassembly and notrecognizing the actual make up of the pull-pull cable system for the stabilator(having two turnbuckles) I put the lower cable on (no turnbuckle take apart)and then with the upper turnbuckle lose I put that clevis on. Near this time Iwas doing this correspondence and Mark said to check the stabilator with downforce 5lbs on the trailing edge and sure enough I have too much. (which likelysplains the lazy lift off). Just now I realize that it is the lower controlstick cable that holds the stabilator when the stick is back.

 

3rd the question: is the “unwinding” of the cable whentension was released something that I should seek to (rewind just a little bit)to keep the “right” twist in the long cable? ( I recognize that I need to takea look at the lower cable turnbuckle in the process.)

 

4th the book:I have an assy manual that says: (a) pull thecontrol stick to the back stop. (b) adjust the lower turnbuckle until thehorizontal stabilator control horn touches the top of the tail boom. (c) adjustthe upper turnbuckle to remove any slack in the control cables.

p.s. this "lazy" stabilator has likely been with me for awhile!Gary