[Ground Slammer]

In this space I would first like to introduce my Quicksilver project, and then start a dialog about my design issues.
The Quicksilver-II project will have 4 phases, and terminate, if it runs to it's full conclusion in an electric self launch, self recovering motor glider. The project starts with the creation of the Quicksilver-II HG (Hang Glider) then this is the wing to which a trike is attached to create a primary tow glider (PTG). How much weight I will have to work with (up to150lbs max) will determine the third phase-adding fairings to create a secondary tow glider (STG). Once then ready I'll add the motor. Right now we will focus on the hang glider.
The hang glider from the start will be created with the end MG ( Motor Glider) in mind. For instance, the HG root tube is a thin wall 1.5 inch tube, and the trike requires a 2 inch square tube. So I will use a 1 5/8th's thin wall tube and saddles, so my mating surfaces come to the same plane as a 2 inch square tube. When the time comes to add the landing gear, the 1 5/8ths will swap out to a 2 inch square with no other changes than bolt off, bolt on.
The HG's improved features over the original Quicksilver are,
1- A Fledge-II airfoil,
2- A trailing edge added to the rear spar,
3- A breakdown feature for the wing so it will fit in a standard tube bag,
4- Advanced wing tip enhancements.

Let me start with the wings breakdown feature. It consists of using U channel brackets to mount the compression struts to the spars. The LE spar's brackets have bolts that act as an axle. The TE spar's brackets have pins that come out to allow the struts to fold along the leading edge. Then the TE is moved along side the LE, the bundle is tied and the wing goes in a standard tube bag. See Sketch.

Wing Breakdown Details 3.jpg (60.45 KiB) Viewed 9066 times

The brackets are 1/8 in thick 6063 T5 with saddles in between the spars and the base of each bracket. The bolts are 1/4 AN4 the pins are 1/4 clevis. Now here comes the tricky part, the gap in each bracket is 1 inch. I feel I need to run a less than 1 inch in diameter compression strut so to be able to place a sacrificial nylon washer in between the strut tube and the bracket. It may be also best to place a nylon or other material collar on the pin end of the strut. 7/8ths inch tube is not cost effective or weight effective. 3/4 has two wall thicknesses that may work and are cost and weight effective. If I use 3/4 inch I can put nylon collars on each end of the strut and when they get chewed up replace the collar.

The standard strut is 1 inch by .049 wall, the options are 3/4 by .058, or 3/4 by .065. Will either or bolth have the compression strength to meet or exceed the standard tube. I know that if the wall thickness remains the same, the cross section area determines the relative strength in compression. Ergo .5 squared x Pi vs. 3/8ths squared x Pi. but I am at a loss to figure the wall thickness contribution. So I could use some help on this computation.
If you, the reader have the math and science knowledge in these areas please chime in. In fact as I go through the plans anything you may see as an error, or have a better proposal chime in. Negative criticism should be constructive negative criticism.

Some basic details of the Quicksilver-II HG. Span 34' cord 4' 3" AR8 Tail group, standard Quicksilver MX less the elevator. Airfoil is Fledgling-IIB root section. Wings have spolierons, the estimated L/D is 14 to 1 and the minimum sink about 120'/min. The wing tips are Quicksilver Ultalight pressure gate with droop tip from the upper edge of the cord downward. Above the cord top the forward section is a Kasper pressure gate and the rear is a plano convex winglet. The top enhancements are optional so in the early phase of practice the stall and tip inertia can be minimized.

[Rick Masters]

Mike Sandlin's Goat
There are a lot of good ideas here.
http://m-sandlin.info/technicaldrawings/td.htm

g1s8.gif    Note that few holes are drilled in the spar or trailing edge tubes.
This eliminates a common failure mode in ultralights.
Of course, this isn't going in a glider bag but it is well-engineered.

[Ground Slammer]

Thank you Rick. I will be spending some time reviewing the drawings. If I were not adding a trailing edge I would have no questions of the ships rear spar.

The next item up for roundtable will be the TE. Do you have any links that I might research these rear spar failures? The Quicksilver B was made to address the rear spar weakness of the original Quicksilver. However my trailing edge will require extra compromise of the rear spar by way of drilled holes ( 3mm or maybe smaller pop rivets-so only a one side hole instead of a though hole.) Right now I am looking for some help with the 3/4 strut wall thickness. But yep, the TE issues are next.

[Rick Masters]

https://www.thrushaircraft.com/getmedia/db3a4c10-c063-4d8e-8a77-b4ab258c58f9/sb-ag-37.pdf.aspx
Cracks grow from holes. Sleeving helps, but a poor sleeving installation can cause spar failure. Hundreds of examples out there. I would definitely look to see how modern ultralight builders have addressed the problem.
It's all that extra weight stressing parts.
I call it hang gliding with an anvil at your back.
Most of my hang gliding friends who got killed went in on powered hang gliders or ultralights.
Power made them lose their minds.
The engines smashed some of them to pulp when they hit.
Stupid waste.
It kinda soured me on 'em.
I'm a freeflight guy.
Where I live, Owens Valley, I got HG flights of 9, 10 hours.
If I had an engine, I have to come down to refuel.
No way.
My good friend Geoff Lyons killed himself on a motorglider on a mountain I can see from my house.
He didn't need a motor at all.
Why settle for second-best?
I don't get it.
Maybe its transportation.
Maybe I need a motorglider to go to the store for milk.
If I lived in Kansas.

[Frank Colver]

On my Skysail (see profile pic) I had no holes in the LE or TE, however it didn't fold for transport either.

TE was 3/4" OD x .022" wall, titanium. Probably the only thing that would have survived the museum fire.

Frank Colver

Building the Colver Skysail wing structure photo.jpg (318.23 KiB) Viewed 9035 times

[Ground Slammer]

Thank you Rick and Frank. I am not savey on titanium, exspensive and heavy is all I know. What is it's electrolytic attitude toward aluminum?

All rear spar holes are already planed on sleaving. All load bearing holes are to be bushed.

I did not go into ulartalights in the past but as electric power starts to come to the horizon I find a 6 pound motor that doesn't use a series of jackhammer explosions to make rotary motion. No glowing hot mantle, no hot muffler, no exhaust gasses and oil condensation, no noise, no restart issues ( essential for motor gliding!) no fuel. Rick I will as I have time go into the rational for this, and it is safety, but I need the time to point it all out. I will say this now-there is a world of difference between a touring motor glider and a airplane that started as a glider, and still a big difference from a touring motor glider and a self launch/self recovering motor glider.

I have 50 years of Quicksilver technical bullitins, and motorized Quicksilvers that take off with 720 pounds of weight. I'm not building a hang glider that one day I discover I can put a motor on it. I'm starting with an airplane that was once derived from a hang glider and going back to the hang glider and making it an electric motor glider. Rick stay with me I seek the dialog!

[Frank Colver]

G.S., I have had five electric motorcycles, 4 commercially built and 1 I built myself, plus 2 e-assist mountain bikes. I also fly e-RC gliders. I am a hopeless addict to electric propulsion :!:

I'm even wondering; if I attach one of my model airplane e-propulsion systems to the kingpost of my Condor 330 how much farther will it "glide" over the beach at Dockweiler. I would call this "e-assist glide" since the glider would not sustain flight with so little thrust. It would be easy to try because someone could be operating the throttle on my transmitter and turn on the power and see what happens after I launch without the assist.

Attached photo of my homebuilt electric dual-sport trike. I've put many miles in the dirt on this vehicle. In 2013 I used Zero Motorcycles entire motorcycle e-drive system to convert it from its original gas powered configuration that I built in 2006. In its first year as e-powered I put more miles on it than in its first 7 years as gas powered.

The titanium tubing was cheap Douglas surplus. Never saw any reaction with the aluminum. My 2" LE was "Rain For Rent" aluminum irrigation tubing, 6061-T6. I wouldn't go more than 1 foot off the ground with that today!

Frank

e-trike above Silver Cyn.jpg (487.31 KiB) Viewed 9023 times

[Bob Kuczewski]

if I attach one of my model airplane e-propulsion systems to the kingpost of my Condor 330 ...

Be ready to push out!!   

[Rick Masters]

Be ready to push out!!

Yeah, no kidding. I'm getting flashbacks of crazy kids with weedwacker engines mounted to the kingposts
of their rogallos, wallowing at stall and slamming into telephone poles while their friends laugh uproariously.
Better not to reinvent past follies but to use what we've learned and refined since then.

Here's one of the world's greatest pilots showing how it's done today:



May not be Manfred:


Definitely not Manfred:


You've come a long way, baby:

[Ground Slammer]

Frank I would at least use a Soarmaster type set up, but you will not need the clutch. Most rag piolots are making mosquito type harnesses and e-powering them.

I do I remember what I called The Soarmaster Trials- -talk about Ground Slamming-power slamming!
This lead from Ground Slamming to Ultra Slamming-and then Para Slamming. Soon every one was some kind of Slammer and there were people slamming all over the place

Yes my first time witnessing The Soarmaster Trials-a 12 pack of beer, a few joints, and a lawn chair -then somebody's thumb started pointing in a direction it never did before At least it was the guy who brought the Soarmasters Ruined a perfectly good buzz

Frank how old is that body of your's? Do it with proper thrust vectoring and so on or- leave it to kids.

Trash Technology Kills