Official Freewing B-2 Spirit Bomber 86" Twin 70mm EDF Jet

[DCORSAIR]

Personally, I take out all the springs and use fuel tubing with o-ring lube. I have a bunch of different diameters and types, because it does require some trial and error per plane/strut. You want to max the diameter of the tubing in the strut without binding on compression. You also want the length to extend the strut to its max length and no more. This also lets the strut compress the farthest. On struts that have a slot on the side, use tygon gas tubing. It's tougher and resists cutting, but also a bit firmer. Silicon will split on the slot's sharp edges.

Typically you lose a small amount of compression versus a spring. The cool part is that it will not rebound, it only absorbs the shock, just like a real a/c shock and the way it's supposed to work. The o-ring lube is essential as it keeps things slippery in there and always lets the shock re-extend.

I know it's not talked about a lot on these forums, however I've been doing this for over 20 years back when we only had Robart struts. I've never had a gear hang when retracting because it didn't extend. I've had much better landings because the plane "plants" when it touches down. Yes, there are times where the plane can jump back into the air, but that's only if you're carrying too much speed anyway. It works and will save a plane from a hard landing. No rebound!

One other cool plus, most planes will sit with the shocks slightly compressed, just like the real thing. Throw away those big nasty springs!

Wow, great idea, may have to try it one day, I have the HSD 120mm T-33 and it has springs but they also have heavy grease inside, it works well too but I cut the spring down and use light grease instead and it works very well, no bounce and stays planted, may have to try your suggestion and remove the spring completely and use the fuel tubing method.

[nuts-n-volts]

Just remember to clean out every bit of the old grease. It does not work well with the tubing. I use alcohol and a twisted paper towel or a swab.

[DCORSAIR]

Just remember to clean out every bit of the old grease. It does not work well with the tubing. I use alcohol and a twisted paper towel or a swab.

Yes, I use denatured alcohol and a rolled up paper towel or swab, thanks for the tips and back to the B-2 topic, yet to get one or even fly one, maybe one day I will give it a go.

[GliderGuy]

Yes, I use denatured alcohol and a rolled up paper towel or swab, thanks for the tips and back to the B-2 topic, yet to get one or even fly one, maybe one day I will give it a go.

Lots of fun and a crowd pleaser….but remember, fly the B-2 on days with less than 5 mph winds IF you want to have her last a long time.

You can get away with a windy day landing, but SHE WILL BITE YOU eventually if you fly in wind.

I made 15 B-2 flights at sunrise this morning, and happily have her home safe. Wind was 4 mph.

All it takes is a gust at the wrong time to cause a crow hop to get going…..ugh!

Order spare nose gear parts to have on hand.

-GG

[Nightmare]

Thanks so much Evan D & nuts-n-volts for your suggestions! I will look into it. I believe Adam (Model AV8R) or Jeremy Solt mentioned something about shortening the springs by one ring or two, but I‘m neither sure nor can I find the video where it was discussed. Anyhow, thanks for your help.

[GliderGuy]

Some might be interested in an update / “How’s the B-2 design holding up?”

With the number of flights on her totaling well north of 1,000, here are my observations and flight conditions. The actual number of flights is LARGE. I’ve made 70 flights since 06/03/23 just to give you a feel for the activity my B-2 is seeing.

- Each flight at least one loop is performed.
- Not much full throttle flying is done.
- Some aileron rolls are done, but this is not an airframe stressing maneuver.
- Several nose gear servos have been replaced due to a bent worm gear.
- CG by the manual.
- Flying mostly at sunrise or near sunset in calm air.
- One inner “elevator” servo failed. This caused an almost uncontrolled landing…hit short and hit a big rock with the nose. Smushed up the nose pretty well. Both inner elevator servos were replaced after the “crash”. The nose foam and nose gear hardware was repaired easily enough. No damage was done to the mains. From the rapid deceleration, the left outer panel spar broke along with the left outer wing plastic mount…both replaced.**

The photo below shows how well the airframe is designed. There is an area of small stress cracks in the foam in the same location on both sides. These stress cracks were present before the landing accident. They are not growing in size as the total number of flights increases.

For the workout she’s received, the B-2 is holding up VERY well. I am impressed!!!

As others have noted, keep all types of the nose-gear area hardware on hand….especially spare servos. You may also keep a spare set of main gear doors. I’ve broken the hinge pins off of the main doors when the nose gear collapses on a bad landing.

For “mostly” trouble free flying, make every landing the best landing you have ever made and fly only in light wind conditions (5 mph or less). Keep her in ground effect a few inches up and HOLD HER OFF as long as possible….touch with MINIMUM energy. Less energy = less bouncing = saves the nose gear servo.

My last nose gear servo replacement was because I landed in a different area. There was a bump in the pavement that launched her into the air at below flying speed. She nosed over about 30 degrees into the pavement. Ruined the nose gear servo’s worm gear.

There is so much weight on the nose gear that you WILL bend the servo worm gear, eventually. Ain’t no way around it. Nobody can make a perfect landing every time. But try hard to!

I enjoy flying the B-2…and what a crowd pleaser she is! I have not found any bad flight characteristics. She’s never tried to bite me. A joy to fly, and be skillful with your landings.

-GG

**To remove the plastic wing mounts, use a cutting disc on a Dremel tool. Then attack the plastic mount piecemeal….remove bits a little at a time. Cut off the 90 degree chord-wise top/bottom corners first and you can peel away the top and bottom strips. Eventually, you’ll get all the plastic off the foam. It is quite a task but with care can be done without damaging the wing foam.

[nuts-n-volts]

Nice report, GG. Thanks!

[GliderGuy]

Nice report, GG. Thanks!

Thanks…added a few more helpful edits.

-GG

[GliderGuy]

Update to post 1406 above….

What an unusual week of almost calm mornings. Just landed my ***100th*** B-2 flight since 6/3.
that’s surely a week’s B-2 record.

Note: The total B-2 flight count far exceeds 1000 flights for this bird.

This special weather can’t last. Gotta take advantage of it while it does.

This morning’s details: 1st flight at 6:05 AM CDT about 10 min before sunrise. 10 flights made by 7:20 AM. (For some reason I am seeing a 6:26 AM post time…odd.). She looks beautiful in the early morning sky.

68F and mostly clear + altocumulus and with good visibility. Wind = calm in north Texas.

-GG

[Evan D]

Awesome, congrats centurion!

[davegee]

Update to post 1406 above….

What an unusual week of almost calm mornings. Just landed my ***100th*** B-2 flight since 6/3.
that’s surely a week’s B-2 record.

This special weather can’t last. Gotta take advantage of it while it does.

This morning’s details: 1st flight at 6:05 AM CDT about 10 min before sunrise. 10 flights made by 7:20 AM. (For some reason I am seeing a 6:26 AM post time…odd.). She looks beautiful in the early morning sky.

68F and mostly clear + altocumulus and with good visibility. Wind = calm in north Texas.

-GG

I thought I was doing well just completing my 26th successful flight today! Good going and congrats on your 100th flight, GliderGuy!

I agree with your above comments about the handling of this airplane. Here in WY, we get a "bit" of wind from time to time. This morning was near calm, and those are my parameters to stack the deck in my favor for a fun and successful flight (hopefully with no damage!) I fly this plane pretty much as a "cruiser" sometimes make a "banana" pass where I go past the extended centerline on a pass, and then swing over the runway in a nice "show pass" good for pictures in this beautiful blue sky we have here. Today's takeoff was a bit of a challenge, as it did a "British Jump jet takeoff" really too early to fly when It bounced off a rough part of our runway, but I kept it down in ground effect for a little bit to build up safe flying speed. Happens a lot, up here, but at least we have a paved runway, which is good.

I'll attach a pic on the set up table as I was taking it apart to come home after my flight today. Also flew my F-4N which flew beautifully on its 27th flight, or so. I've now flown all my jet warbirds in the past week, a T-33, A-4E, F-4N, B-2, and F/A-18C. All fun but challenging to fly (for me).

[GliderGuy]

Thanks Davegee and Evan….

Good job handling the “ski jump” take-off and for the summary of your flights. Better to happen on take-off than landing which can be followed by a drop-in and a damaged nose gear servo.

I added a note to the 1409 post stating that my B-2 total flight count for this bird far exceeds 1,000 flights.

The weekly total of 100 is submitted for a record of sorts for 7 days. Need to call Guinness.

-GG

[davegee]

Thanks Davegee and Evan….

Good job handling the “ski jump” take-off and for the summary of your flights. Better to happen on take-off than landing which can be followed by a drop-in and a damaged nose gear servo.

I added a note to the 1409 post stating that my B-2 total flight count for this bird far exceeds 1,000 flights.

The weekly total of 100 is submitted for a record of sorts for 7 days. Need to call Guinness.

-GG

Wow!!! Totally cool !! I figure if I get 100 flights total out of my B-2 I'll be happy. More power to you having that many!!!

Davegee

[TwistedGrin]

Gents - I am flying off of grass field....had several successful take off and flights and only one clean landing without the dreaded pogo agoggo landing. I tried the single wheel main gear that may have helped take off some - but the landing I am sure was way to0 springy......I think the drag of all eight trucks should be way better than the single wheel to bleed off landing landing speed.

I have made repairs and put the stock main quad trucks gear back on ready to try some more....

Been so long since I flew it.........is there a general consensus the marked CG line on the bottom side is correct....no need to experiment with the CG?

Thanks in Advance

TwistedGrin

[GliderGuy]

Hi TG,
I fly at the CG mark. The secret is land with as little energy as possible. No energy = no bounce.

Try this:
1) On final, smoothly reduce to ZERO power.
2) Bring her down to a few inches and hold her off.
3) Do NOT let her touch….Hold her off as she bleeds energy. The wing won’t drop in ground effect.
4) Once she no longer has the energy to fly, she will settle in nicely. You may even touch with full up elevator.

Do this right and she has no energy to bounce.

Over 1,000 landings I have made with the B-2 have verified this works.

Also, do not fly in wind more than 5 mph. If I get to the field and the wind is blowing more than 5 mph, I fly other birds. All it takes is a gust at just the wrong time, and your landing will be a disaster.

-GG

[Aros]

Hi TG,
I fly at the CG mark. The secret is land with as little energy as possible. No energy = no bounce.

Try this:
1) On final, smoothly reduce to ZERO power.
2) Bring her down to a few inches and hold her off.
3) Do NOT let her touch….Hold her off as she bleeds energy. The wing won’t drop in ground effect.
4) Once she no longer has the energy to fly, she will settle in nicely. You may even touch with full up elevator.

Do this right and she has no energy to bounce.

Over 1,000 landings I have made with the B-2 have verified this works.

Also, do not fly in wind more than 5 mph. If I get to the field and the wind is blowing more than 5 mph, I fly other birds. All it takes is a gust at just the wrong time, and your landing will be a disaster.

-GG

Heed this man's advice!

Sincerely,

Common Sense

[TwistedGrin]

10:4 Thanks Gents - will adopt long low energy ground effect landings as SOP !!

TG

[GliderGuy]

After take-off and the first overhead pass, a right banking action was noticed. It wasn’t severe and was corrected with aileron and drag rudder trim.

I flew it a few more passes to get the feel of how she was responding. Once re-trimmed (several clicks), she handled ok. Since she was wanting to bank right, it was decided to a make left pattern to avoid getting the right wing down.

The landing was uneventful, but an observer walked over to stand behind my truck as I turned final. LOL

Post flight inspection: The right aileron servo was frozen with about 40 degrees up deflection. WOW! I could not believe my eyes.

She had totally benign handling characteristic even with the large amount of up <right> aileron. Good design to have absorbed the asymmetrical aileron deployment and still fly OK.

Now to replace both aileron servos. I may have reached their MTBF point.

- GG

[F106DeltaDart]

Wow, excellent save! Nice flying GG!

[GliderGuy]

Ref post 1418 above….

Test flew this morning, and all is well.

The Freewing stock servos lasted well over 1000 flights and likely close to 2000 B-2 flights. During this “workout”, one inner elevator servo failed and one outer aileron servo failed.

The lesson to be learned…1) probably a good idea to use a more expensive servo on any bird with a critical single point of failure like the F-4 elevator and P-38 elevator. 2) The stock FW servos stand up to use pretty darn well. Most folks won’t see a failure with “normal” use. I take “use” to the extreme.

I have now replaced ALL the control servos on the B-2 with the exception of the drag rudder servos. Went back with stock FW servos.

-GG

PS Additional data points….all birds below have exceeded 1000 flights each (close to 2000). All use the “same” FW servos:
PJ-50 = Replaced one aileron servo
AL-37 = Replaced 0 servos
P-38 = Replaced 2 aileron servos and upgraded the elevator servo
F-4 = Replaced 1 rudder servo and one aileron servo and upgraded the elevator servo

Not a bad performance, overall. But, upgrading may be warranted, if you want fewer failures.

Again, most folks are unlikely to ever see these failures….with “normal” use.

All but 2 frozen failed servos failed in the neutral position. If they are gonna fail, that’s the best position to fail in. Most of the failures were detected during the pre-take-off control check. That’s REALLY a good place to fail.

Some were replaced because they developed the “jitters”.