DR-1 (Sands): Builders Group

GoldenAge · 14 March 2010, 08:08 AM

Hi Guys,
Thanks for the quick reply on the gauge question. That's what so great about these forums.
Paul

Jeff Brooks · 14 March 2010, 08:27 AM

Quote:

Originally Posted by Chill31

In addition, if anyone has any parts or building materials/supplies that they are willing to sell, please let me know. I am US based.

I still have 2 compasses left,
I have brass fokker style wing nuts(threaded for AN3), Vet has the steel version (threaded for metric).
I have a couple of DVII throttle quadrants that would look about right on a tripe
I know Tony Moore & Pavel make fokker style turnbuckles.

GoldenAge · 15 March 2010, 09:04 PM

Hi Guys,
Here's a good one. Does anyone know what the aileron travel limits are? As you know by now we are building this airplane using Sands plans as engineering guidance. We are also using many other sources for reference. The problem that has popped up is the aileron travel. The airplane is set up with the four aileron cables as per the original. The control horns were built and set by the Sands plans.

Here's what happened. I started to manufacture the aileron cables. When I started to check the travels I found that the control grip hits the throttle on the left sidewall. I also realize that the throttle was not there on the original but Ron Sands has the grip throttle and the sidewall throttle. Has anyone else had this problem? The other issue is that while sitting in it I could never move the stick that far, my legs get in the way. When the stick gets to the full travel I get 30 degrees of aileron deflection. Looking at the Sands drawings at first glance it looks like the travel should be 30 degrees. Upon further study it might not be so. The 30-degree arc on the print does not measure from the center of rotation of the aileron tube/spar. It measures from the stop cutout to the front surface of the horn and spar. It looks like the movement will be more like 26 or 27 degrees.

Did Ron mean that the travel should be 30 degrees? 30 seems like a lot?

To the guys that are flying, how much movement do I really need?

Has anyone added limit stops at the torque tube in the cockpit?

Did I screw up?

Any guidance would be great!!!!!
Thanks,
Paul

GoldenAge · 18 March 2010, 06:31 PM

Well I guess everyone else is stumped with this as well? I have been studying this aileron movement problem over the last few days. Here is what I found out: It appears that the angle between the control horn and stop on the original airplane is 20 degrees, not the 30 Sands calls for. The aileron horns on the original lean forward slightly, Sands' leans rearward. This should allow for more travel. The only other issue is the original airplane has a larger space between the aileron and the wood spar. Sand's has less, this might also account for the reason he leaned the horns back.

All of this still didn't make much sense yet I was concerned that I did not have enough aileron travel. I called Roger Freeman and his comment was, "don't over think it, you will not run out of travel". He does agree that it will never move 30 degrees. The limiting factor is the pilot’s legs. I guess he is right. It just seems hard to believe that Sands would design and build the airplane this way. Did the original do the same thing? Probably. It almost has to because of the design of the system.

So with all of the research this is what I did: The stick hitting the throttle bothered me. Also while sitting in it my knee would get stuck between the throttle and the stick limiting the travel further. I got out my hacksaw and did some demo! I built a new throttle bracket and moved the throttle aft 4.5 inches. It solves the problem of the knee pinch. The ailerons still only move to about 24 or 25 degrees with me in it and the stick not hitting anything. (I plan to change the stops so the stick will not hit anything with the cockpit empty.) Next I moved the tachometer again for fun. The oil pulsometer on the right side had to be lowered. The whole arrangement works much better.

Now with that solved here is the next problem: I started building elevator cables today. Figuring in the ammo box and the Bowden cables for the triggers there is no way to get enough stick travel for 30 degrees up and down. Here we go again

! Redfern called for 30 up and 22 down. I am sure this will be enough if I can get it. To get the 30 I will need to go on a diet and pulling the stick that far aft will probably fire the guns and depress the blip switch against my body. Roger recommended installing the later style grip to help with the Bowden cable clearance. I don't know if that will help, I like the early grip anyway. If anyone has any advice on the elevator travel and stick clearance please share it.

The last thing is the first of the new oil pump parts showed today, the cast aluminum housings.

More progress soon,
Paul

The rearranged cockpit.

Aileron torque tube horns and turnbuckles.

LeRhone oil pump housings.

Dogtail2 · 20 March 2010, 06:00 AM

Quote:

Originally Posted by GoldenAge

Here is what I found out: It appears that the angle between the control horn and stop on the original airplane is 20 degrees, not the 30 Sands calls for.

Hi Goldenage,

I built my controls as per Sands drawing as at least 2 tripes here are flying successfully with this config. As a first time builder, Im using the philosophy of ... 'If it aint broke, dont fix it'.

Where did the 20 degrees dimension quoted above come from? As I understand it hardly any original drawings exist. Was this angle guessed at from photos or do you have some original drawings?

Im a bit confused about your throttle postion as you say you have moved it 4.5 inches back, yet it appears to be in the same postion as mine. Mine is as per Sands drawing.

With the ammunition box in place I think I was getting 20 degrees down elevator. I'll check when I reassemble the aeroplane and let you know.

GoldenAge · 20 March 2010, 11:29 AM

Hi Dogtail,
Thanks for the reply. I have been watching your progress for inspiration over the years.
The 20 degress I found in Paul Leaman's book, I don't know for sure where he got it.
The mixture lever on the original appears to have been farther forward, mounted on or just aft of the vertical tube. I had the two levers installed there and found that it didn't work well. That is why it looks like yours now, it is just about where Sands calls for it.
The down elevator we are working with now. We are building the ammo box and will get a final dimension on travel when that is installed. I believe the original used the ammo box as the forward limit. The travel in all of the old photos shows very little down elevator. With the exception of the crashed airplanes, I think that on impact the stick was driven into the ammo box and thus creating more down elevator.

On a new topic, we were watching your youtube video with your wife painting the wing. What product were you using? Dope, paint, etc. Is the brush course or been modified?

Thanks for the information, I am looking forward to seeing more of your progress,
Paul

Quote:

Originally Posted by Dogtail2

Hi Goldenage,

I built my controls as per Sands drawing as at least 2 tripes here are flying successfully with this config. As a first time builder, Im using the philosophy of ... 'If it aint broke, dont fix it'.

Where did the 20 degrees dimension quoted above come from? As I understand it hardly any original drawings exist. Was this angle guessed at from photos or do you have some original drawings?

Im a bit confused about your throttle postion as you say you have moved it 4.5 inches back, yet it appears to be in the same postion as mine. Mine is as per Sands drawing.

With the ammunition box in place I think I was getting 20 degrees down elevator. I'll check when I reassemble the aeroplane and let you know.

Dogtail2 · 20 March 2010, 01:13 PM

Hi Paul.

Before you make the ammo box, make a cardboard template and suspend it in the correct location and check that you have enough clearance for your legs when moving the rudder pedals. I made my ammo box and found that it was too deep and interfered with my shins. I then had a fun job of shortening the box by a couple of inches.

For painting the wings I used thinned Randolph olive drab butyrate dope and an ordinary 4" (100mm) household decorating brush.

Keep the photos coming. I think you will overtake me pretty soon unless I get my finger out

gipsymoth236k · 20 March 2010, 01:24 PM

Here's the original Dr.I aileron control horn configuration.

Regards,
Gary Sewall

GoldenAge · 20 March 2010, 05:36 PM

Hi Gary,
Thanks for the print. It looks like the 20 degree stop that Leaman has in his book looks right. It looks just like your print. Sands did not add the extra wood between the rear spar and the aileron horn so using the horns as per original one would have to cut too much wood out of the spars for the stops. His solution was to lean the horns back. If I would have caught this earlier I would have made the rear wood spar as per original and leaned the horns forward. Too far along to make the change now. I am able to get about 25 degrees of aileron travel with Sands horns and the D.VII style pulleys with four cables.

Thanks again for the info,
Paul

Quote:

Originally Posted by gipsymoth236k

Here's the original Dr.I aileron control horn configuration.

Regards,
Gary Sewall

GoldenAge · 20 March 2010, 05:44 PM

Hi Dogtail,
Thanks for the heads up. I did catch the problem with the box. I clamped in a piece of wood at the suggested bottom of the box and also found that my shins would not clear. I am 6'1" and I need all the room I can get in this thing. I built the box today, it was shortened by a few inches from the print. I made it hang 11" from the bottom of the longerons. It gives me lots of room. I am making a few other changes to it that will not bee seen when finished. I am working on the machine guns and making them propane gas firing. The gas canisters and some of the electronics will be in the ammo box.
Thanks for the tips on the streaking. Using the dope, did it tend to loosen up the coats underneath while you were brushing it?
Thanks again,
Paul

Quote:

Originally Posted by Dogtail2

Hi Paul.

Before you make the ammo box, make a cardboard template and suspend it in the correct location and check that you have enough clearance for your legs when moving the rudder pedals. I made my ammo box and found that it was too deep and interfered with my shins. I then had a fun job of shortening the box by a couple of inches.

For painting the wings I used thinned Randolph olive drab butyrate dope and an ordinary 4" (100mm) household decorating brush.

Keep the photos coming. I think you will overtake me pretty soon unless I get my finger out