My E-Flite Blanik Build

[Mark9]

Well, it’s taken some time and the Blanik is ready to maiden, can’t think of anything else it has to have to fly. May be a pilot? I’ve decided to use what I have installed as far as nose weight, the last picture posted above shows my ballast installation. As best I can tell on the Vanessa rig the CG is now at 25 mm. The LE of the blue tape in the attached pictures is at 20 mm aft of the LE. The marks are self-explanatory on the tape. I’ve heard of many flying it at 40-50 mm and liking it. So, I’m fairly confident that I should be able to handle it.

My SD-10G is all programmed and ready with the stock throws. Even have some thermal camber on the left slider, like my TD ships. One of my flying buddies told me of how to set up the flap linkages to not have the flaps drop when the radio is powered off. Using a ball link on the servo horn one sets the rod length so at full up the servo horn points forward, neat trick. Took a little fiddling to get the rod length right though.

Now I just need to wait till our local aero tow group is ready to meet again. The paint touch ups will wait, we have had a bad spring for any work outside or flying not to mention painting! Since I had it together on the CG rig and the garage door open also took some pictures of it in the front yard. Will need a taller ladder to get a full span overhead shot. Will let you guys know how the maiden goes when that happens.

Mark

[Steve P]

Congratulations!

[lenb]

Great Mark!
I watched the guys tear up the sky's this weekend at the Windy Ridge Aerotow. This plane has a fantastic flight envelope. Good luck ( not that you need it ) with the maiden

[ARUP]

Nice tip with the flap links. I forecast an uneventful maiden but beware sore 'grin' muscles!

[Sinkhappens86]

Can't wait for the flight report!

[Mark9]

I know it's been quite awhile since I posted in this thread. We have had problems locally getting a group together, but that appears to be changing tomorrow. The tow plane is in good condition I'm told, we have a tow pilot and the WX looks good...a little warm though. About a week ago I was able to put another 1/2 lb. of lead in the radio tray location and my CG rig says I'm very close to the front of the recommended range.

Always a good thing to be conservative with a new airplane. Also, as I get more confident with the airplane I can easily remove 20 oz. in increments quickly with no tools at the field. I'm ready to see it fly...received the big box about 10 1/2 months ago! Hope to have a good flight report tomorrow evening.

[Sinkhappens86]

Good luck on the maiden! I'm sure it will fly great!

[lenb]

Thats great Mark, looking forward to the glowing flight report

[Mark9]

Well, here’s the flight report from the maiden yesterday of my first ¼ scale aerotow glider, some good and some not so good and sorry it’s wordy! First off the crew of the sod farm had decided the day before to run the sprinklers, we have not had rain here for about three weeks. As a result we were in a cramped area where we have never flown for takeoff and most importantly landing. Some rather deep trenches were in the takeoff and landing area. Those tires for the big rotating sprinklers can make a deep trench in wet sod.

The takeoff was uneventful, but the Blanik was towing low and I had problems getting it up behind the tow plane. Josh, the tow pilot, commented that I was pulling him nose up, not sure why. I would pull some up elevator and it would come up behind a little, but drift back down. Could it be, after all my concerns, overly nose heavy? When Josh called for release I had problems releasing the tow from my ship, even though I tested it OK before the flight and we retested it after I landed. The line was lost at some time during the flight since Josh blew the line and I had released it more than once as well.

Once released the airplane stabilized and after playing with the elevator trim some it was responding very well. This bird wants to fly and seemed to be already telling me, “I’m in lift turn here”. But being a maiden I wanted to try out handling and check radio settings, thermaling can come latter. My aileron to rudder mixing looked good for a start and very little rudder input was required…the turns were sweet with almost no yaw. Not too sensitive on elevator but responded well. I didn’t do any stalls though.

Tried the flaps a few times at altitude and the elevator compensation didn’t look too far off. After a few minutes I was low enough that I decided that I should make my landing approach. As I set up I realized I could not get down between the trenches we were taking off from and some of the guys were landing in. This airplane has for its size and weight a very good L/D.

This is where I performed poorly. I had to stretch the landing to get over the last ditch before a wide expanse of new Bermuda. Didn’t want to hit it since I have seen major damage caused by hitting them in the past. Bounced her a couple of times on the other side of the ditch and heard a crack. Broke the former at the back of the cockpit just above the combing on both sides and I also found a crack where the radio tray separated on the port side from the fuselage skin. Later one of the guys, a good pilot from what I’ve seen, told me that was not a landing that he expected I would do. I agree he is correct.

However, repairs are commenced. Fiberglass will be run down both sides of the radio tray junction with the fuselage skin and I am developing a plan to repair the former at the aft end of the cockpit opening. I am thinking about the G10 hoops that Gunny sells, if I can get them in time. However, I’m not sure if the one I need most will bridge the breaks. But, since I removed the CG ballast and battery to make repairs this will give me a chance to modify the wiring to my battery to simplify charging. I was reluctant to do that since it’s a minor chore to pull all that lead, the battery and put it all back. Need to get ready for the Mickey Sullivan in less than two weeks.

[lenb]

Hi Mark,
Well, glad to hear the plane is flying good and you like the way it fly's. Sorry to hear about the mishap, although those things happen.

On my Blanik I removed the former you are talking about, including up around the fiberglass flange in front of the top window and made it out of 1/4" aircraft ply. When removing it, there is some chipping and such with the flange, but after you epoxy in the new one a little paint fixed everything.
Then we have gone to fiberglassing up the top window and making a silver or black window out of a vinyl sticker and placing that on the top of the fuse. It makes the top area much stronger and have not seen any issues there since.
The reason that former cracks is from the wings compressing forward in a non glamorous landing.

Len

[Mark9]

Thanks, I have seen the glassing in of the windows and had hoped I could avoid that. May do that after the Mickey Sullivan Aero Tow. Also, I have put in a call to Aircraft Concepts about his frame hoops. Haven't heard yet of the availability of them and when I could get them. May need to fabricate a former reinforcement from aircraft ply myself. I leave for Milton Thursday week and would like to take the Blanik to give it a go again. Replacing the former entirely will need to be a winter project.

Put the small chunk of former that broke out back in this morning so I have a shape to work to with minimal fill work. Glassing of the radio tray starts today and I've been looking at how to remove the excess epoxy and spooge on the back side of the former to get a good bond with minimal gaps.

[ARUP]

Bummer about the landing. Seems like you have remedies under control. I have two of these kits and will try to build one soon. I'll use all the info posted by previous builders to enhance it.

[gunny11]

Hi Mark, was good talking to you earlier today. Hope I was able to help.... What Len says, is correct about the Windows just in front of the wing. On a sudden stop the wings do flex forward and pinch the fuselage thus causing the cheap plastic to shatter. Install the G-10 frame and if the clear plastic breaks, just replace them with PETG plastic or give me a call. I replaced mine from the get go. Laser cut windows are on file.
The correct remedy of this pinching situation (which I have done) is to have both of the trailing edges of the wing secured to the fuselage. I.e. Tab and screws.

[Mark9]

Yeah, enjoyed talking yesterday as well Gunny.I assume the tab and screws are external? I have short arms and had to develop extension tools when working on the former at the tailing edge. Was real fun when I reinstalled the former in front of the vertical. It basically fell out of the airplane...probably only bonded over less than 25% of the surface area. This is my first ARF, other than high-end molded TD gliders, and quality control appeared to be less than stellar.

OOH, thanks for getting my parts in the mail yesterday. That should give me adequate time to get it all ready before I leave for Kansas. Now just need to get one of my cats well too. He developed a bladder infection yesterday. Always fun giving them medication!

[ARUP]

Giving cats medicine and 'herding cats' are kinda the same thing, right?

[Mark9]

Thought I might bounce this idea off all of you more familiar with this aircraft than I am. As you may have read the maiden didn’t go as I had hoped and I damaged the former just aft of the canopy. Talking with Gunny at Aviation Concepts a possible solution he mentioned got me to thinking about how to possibly stop a recurrence of that problem with little complication. It's repaired now with the help of some frames from him. The hypothesis is that the wing flexes forward on landing causing crushing of the former.

My thoughts are to fabricate a sheet metal plate of either aluminum or stainless steel, I hate rust. And this would be attached on to the underside of the wing root fairing externally with screws into the plywood doubler in the fuselage. It would be located well aft of the incidence pin, but forward enough to get a good bite in the root structure. The plate would remain fixed on the fuselage.

A single screw would then be inserted through the plate into the plywood root rib of the wing when assembling the airplane at the field. A hard point could be used, such as a brass insert, allowing the use of a 6-32 or maybe an 8-32 machine screw if the 6-32 is inadequate. It would add a little aerodynamic drag, but I think the penalty would be worth the cost.

First of all would help it enough to prevent crushing of the former? Granted we can’t make them crash proof if we expect them to fly. But, I’m interested to hear comments and constructive concerns. Please keep in mind I have only a small portable drill press, a bench vise and typical hobby tools with which to fabricate the parts for this modification.

OHH, BTW ARUP he has been amazingly behaved when administering his antibiotic.