Vintage Tug - BH Storch ?

[ARUP]

The vid sure shows a fun airplane!

[Joespeeder]

Hey Guys,

First steps.... Took the Storch to the field for the first testing. Fired the engine, taxied a little, and just generally figured out how to work with it in general.

It it needs some things, nothing life shattering. Axle work as I had one wheel hanging up, some tuning, and stuff.

Most of all I need to up size the prop load. I'll do some calcs to see if I want diameter or pitch... The Laser was turning 9,090rpm on a 21x6 which is over 40lbs thrust and 50mph pitch speed. 9,000 is the very top of the recommended rpm range. So I'll get the rpms down a bit with more prop.

Getting the Storch in and out of the car was part of the learning curve. I'll get better as time goes along.


Joe

[Joespeeder]

More pics from last night.

[Joespeeder]

and some noise..

[Swiss1]

Nice pics, but it say's the video is not available!

Jeremy
SCCAAA TT TN

[Joespeeder]

Try now...

[kjkavaney]

I get about a dozen U tubes but nothing with your plane...sorry...keep trying...would love to see it..
kevin

[Joespeeder]

In the post above there should be a window with the Storch in it. Click on the window and it should take us you to YouTube.

Sounds like it's still hanging up somewhere. Works here so I'm at a loss how to fix it.




Here's the raw YouTube link without using the forum hyperlink function.

https://youtu.be/KaMEoGMX7do

Copy and paste it into your browser. It may go direct with a click but I'm not sure at this point. lol


Its just just a quick vid of the engine idling.

Joe

[Joespeeder]

Hi Guys,

I'm happy to report the Storch flew last night. Whewwww..... I'm still tuning the 300v as I'm not good at tuning and my learning curve on dual carbs is bigger than most. But I finally, got it to a point where I thought it would fly. I was dropping a cylinder and then thought I had it. Well, I'm close but not 100% yet.

The Stroch has been the most interesting and weird set up process I've done so far. My Grafis Maxi was difficult but it all made sense and I had good info on settings... To look at the Storch you'd think it was very simple but far from it and finding good info is difficult to get.

BH gives you a plywood template that is used to set the flaps and ailerons to neutral. Be sure to get everything set mechanically as close to symmetrical on both sides of the wing for both sets of surfaces. The surfaces are hinged kinda like Fowler flaps in their movement. So mechanical set up being very close is critical.

Important bits...

You don't need lots of speed, so increase your prop diameter until your pitch pitch is reduced to 45-50 mph. I wound up at 45mph and its fine. I also have 2:1 thrust at full throttle which really helps the feel of the Storch in the air.

A YouTube search will find many videos of guys struggling to fly the Storch. So I went looking in all the forums and grabbed a copy of the Full Scale Surface Deflection info.

Per the German forums CG the Storch measured from the front edge of the SLAT at 140-150mm. There are guys flying it at 115mm from the front of the slat it will fly there but not slow. My working theory is that they are using the leading edge of the slat as the leading edge of the wing and overflying the slat. the 30mm difference is the amount of distance the slat adds to the width of the wing. I set mine at 145-146ish just slightly nose down. Just barely. I have a 26oz tank to fill so the 146ish seems safe within the range. It was. It flew very nicely there on it's maiden. I can fine tune as I get more time on it.

Elevator per the German forums is 30mm up and 20 or 25mm down. However, the full scale Storch used as much as 45 degrees of up if flown nose heavy or 40 degrees up of normal if tail heavy. So I dialed in 30mm up on low rates and 40mm on high. I need to mechanically adjust my push rods to get the full 45 degrees. I flew the maiden on high rate with 30% expo on both high and low. That worked great. I used full elevator in the last couple feet when landing and was glad I had it. I could use the the full 45 degrees. I will bump the expo a bit more. 35% I think and then tune thill I like it. But it was a good starting point that felt good as a basic starting point. No surprises.

Ailerons 50% differential. Standard stuff there. I used 20% expo as I want the roll axis to feel positive at first.

Now the tricky part.

The full scale has the ailerons act as flaperons when the flaps go past 20 degrees. At max flap which is 40 degrees the ailerons move down to 20 degrees. At 1/2 flap and above the flaps are in their neutral postion.

I combined the the above settings with the set up the German RC flyers of the BH found worked best for them.

The German flyers dial the entire rear surface of all the wing surfaces downward by 5mm as their neutral setting for the wing with no ability to change the undercamber from the Tx. Use the template to see the amount as you dial it it.

I modified their set up. I put this on my slider that is below my right index finger. Slider forward and the surfaces are neutral, move it to the rear position and the surfaces move down to the 5mm down position. Ailerons and flaps are now all 5mm down to create undercamber. This is your normal cruise around slow position. Flys nice there. If I'm going to tow a faster sailplane I intend to fly with the surfaces neutral in the position BH shows a neutral. Otherwise, I'll cruise around with the wing undercambered. The German guys made the undercambered position their neutral.

Flap switch moved to the middle position drops the flaps to 20 degrees down when the undercamber slider is rearward (undercambered wing) this gives the aileron undercamber and flaps a total of 20... If I close the undercamber slider then the flaps will go slightly less then the 20 degrees and the ailerons are factory neutral with no undercamber.

Flap switch moved to full down drops the flaps to 40 degrees and the Ailerons drop to 20 degrees. This is measured with the wing undercambered. So I can never go beyond the 40/20 position. If I move the undercamber slider it reduces the ailerons and flaps total deflection by a few degrees. The 40/20 positions are from the full scale spec and pilots report to not let the Storch stall from this position. It rolls onto it's back and you need altitude to get it back. Most 3 point landings are done with 1/2 flap positions.


So this all seems simple now but after watching a bunch of weird videos with poor results I went slow and combined both known set ups with the full scale specs. Normal take off and flight with wing undercambered, faster glider tow with wing neutral, 1/2 flap is up to 20 degrees with and without undercamber, and full flaps at 40 degrees and aileron droop at 20 degrees when full undercambered,, a little less without undercamber. Plenty of thrust but slow pitch speed and it gave me a nice maiden flight.

I still have some engine tuning to do but she had air under her wings !!

Hope this helps someone down the road.

Joe

[Joespeeder]

Hey Guys,

A quick update from things I learned last season.

All the flying and set up notes above are still on point and I'm very happy with the way the Storch flys.

I'm not an engine tuner and the Laser V twin challenges me as it has dual carbs and I struggle a bit but I got a lot better figuring it out.

In my flights I found the engine wanted ducting instead of a big opening in the front. So I ducted the air to the cylinders which focused the air and cut down my intake to the area just around the heads. That helped a lot. Everything stays cool now as I have well over the 3:1 exit to intake ratio now and focused to where air is needed.

I'm going to play with props a bit this year and think I can get the Storch to a good consistent tug platform. As an air frame I think it's awesome, Laser Engines are awesome and I'm just a sucky engine tuner that loves that great sound of the V twin. So I'll work on it and get it finalized. Always learning !

Here's some shots of the Storch from last years FAT Fest.

Joe

EDIT: Every time I try to link the video preset to the Storch parts it loads in the bottom panel and starts from the beginning of the video.
So just copy and past the above into your browser. It'll open at the Storch parts.

https://youtu.be/JorUbq8l9mo?t=729