Float plane issues

O

OBIO

Retired SOH Admin
I am working on a CFS2 Spitfire Mk VB Float Plane by Merlin66 (he did a nice series of early Spitfires, FSDS2, all animations work in FS2004, worth checking out, in our CFS2 library). Redoing the skin on the plane, added FS2004 lights and effects.

The plane will take off from water as pretty as you please. But will not land on water...even with speeds as low as 60 knots (which is as slow as I have been able to go without the plane stalling and falling out of the air). As soon as the floats touch the water, the sim registers it as a Crash. I have checked, checked and rechecked the contact points, made some tweaks here and there to better match specs from float planes that work very well...but I still get crashes when the floats touch the water.

Could someone with more skill/luck than I have take a look at the contact points and see if anything jumps out that could be causing this issue?

[contact_points]
static_pitch = 4
static_cg_height = 5.7
tailwheel_lock = 0
gear_system_type = 4
max_number_of_points = 9

point.0 = 4, 3.06, -5.523, -6.139, 7500, 0, 0, 0, 0.8, 1.5, 0.98, 0, 0, 4, 0, 0
point.1 = 4, 3.06, 5.523, -6.139, 7500, 0, 0, 0, 0.8, 1.5, 0.98, 0, 0, 4, 0, 0
point.2 = 4, -9.25, -5.5, -5.95, 7500, 0, 0, 0, 0.8, 1.5, 0.98, 0, 0, 4, 0, 0
point.3 = 4, -9.25, 5.5, -5.95, 7500, 0, 0, 0, 0.8, 1.5, 0.98, 0, 0, 4, 0, 0
point.4 = 2, 3.2, -18.4, -0.652, 1750, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0
point.5 = 2, 3.2, 18.4, -0.652, 1750, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0
point.6 = 2, 4.9829, 0, -3.0812, 1750, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0
point.7 = 5, -10, 5.5, -6.2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0
point.8 = 5, -10, -5.5, -6.2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0

OBIO
 
Obio, what is gear_system_type= 4 ?? try changing it to 0 I know there are a few electric Hydraulic never come across type 4.

Otherwise I can see nothing glaring there
 
Sometimes, when you are totally lost and confused, it is best to start back at square one. So, here are the original contact points for the Spit VB float plane.

[contact_points]
static_pitch = 4.00
static_cg_height = 5.7
max_number_of_points = 7

point.0 = 4.000, 3.060, -5.523, -6.139, 5200.000, 1.000, 0.000, 0.000, 0.250, 1.500, 0.980, 0.000, 0.000, 2.000, 0.000, 0.000
point.1 = 4.000, 3.060, 5.523, -6.139, 5200.000, 2.000, 0.000, 0.000, 0.250, 1.500, 0.980, 0.000, 0.000, 3.000, 0.000, 0.000
point.2 = 4.000, -9.255, -5.523, -5.950, 5200.000, 1.000, 0.000, 0.000, 0.250, 1.500, 0.980, 0.000, 0.000, 2.000, 0.000, 0.000
point.3 = 4.000, -9.255, 5.523, -5.950, 5200.000, 2.000, 0.000, 0.000, 0.250, 1.500, 0.980, 0.000, 0.000, 3.000, 0.000, 0.000
point.4 = 2.000, 3.200, -18.400, -0.652, 1200.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 5.000, 0.000, 0.000
point.5 = 2.000, 3.200, 18.400, -0.652, 1200.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 6.000, 0.000, 0.000
point.6 = 2.000, 11.200, 0.000, -4.400, 1200.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 4.000, 0.000, 0.000

The first two float points are the forward most float points...and they are right under the pontoon pylons....which are pretty much in the center of the wing...making these float points nearly half way back the length of the plane. If I move these forward, the plane will shimmy and shake sitting on the water, but goes as smooth as silk once in the air. No matter what I have tried, the plane either crashes as soon as it touches the water, or once I got it to touch the water without instantly registering a crash, it went nose first into the water due to the forward float points being set so far back.

If anyone is willing to take a look at this plane with the hope of getting it to land on the water, I will be more than willing to ship you the plane, the sound pack I have put together for it, and the revised skin (nearly done...have to finish the belly between the wings).

OBIO
 
2 are scrape points, right? And 4 are float points. So if the scrapes are well inside the floatpoint box you should be in clear. And while you're at it: why not add waterrudder? Gear 5 at rear end of the floatbox, controlled with shift w.

cheers,
Sander
 
I had the same problems with an Albatross and Beaver. I'll go back and see what I did to fix those. I know one was improper placement of scrape points and I think the other was adjustment of compression ratio or damping or something as I believe those are still in play. Both needed a lot of float point adjustment. Just glancing at the numbers the ones before and after the ratio seem rather extreme. I also find it helpful to create lights to show where the points are so I'm not totally in the dark about where things are. Just a thought
 
OBIO,

Send it to me ... I love to do this stuff. :)

I think the biggest problem folks have with doing float contact points is they put them too far foreward and aft.

I place the forward points about where the widest part of the float is, the most buoyant, thickest part.

The rear points should go where the "step" in the float is.

The water rudder points should be at the pivot points of the rudders.

Adjust for best "ride"(taxi and "after-landing"), AoA sitting on the water (rear part of float lower then front, and front sitting more "on top" of the water than in the water), then tweak for overall depth, and rising up on the step on takeoff. Ensure crash points are at or above the waterline.
 
OBIO, i can't seem to find the aircraft... was on my list of aircraft to profile art up, maybe not being able to find it is incompetence on my part but then again it could just be well hidden :icon_lol:
 
Milton

Thanks for the willingness to take a look at this bird. I will get it packed up and sent to you...may have to send it in 2 or 3 parts. I have 2 skins pretty much done for the plane.

Tim

The bird is sent. In one package even. I did not send the sound pack, so you will have to re-alias the sound.
 
If you haven't changed the CoG and CoL positions, I have it done already based on the download here.

Otherwise, I will adjust to your new setup.
 
Milton

I try to avoid changing the COG on planes. I have very bad experiences with that. Explosions, flipping planes, planes that fall over on their noses.

OBIO
 
Okay, here is what I have developed from the raw download. Note I also added a water rudder.

[contact_points]
static_pitch = 3.00
static_cg_height = 6.6
max_number_of_points = 9

point.0 = 4.0, 9.060, -5.523, -7.1, 3000, 0, 0.00, 0.00, 0.85, 2.50, 0.65, 0.00, 0.00, 0, 0.00, 0.00
point.1 = 4.0, 9.060, 5.523, -7.1, 3000, 0, 0.00, 0.00, 0.85, 2.50, 0.65, 0.00, 0.00, 1, 0.00, 0.00
point.2 = 4.0, -2.855, -5.523, -6.5, 3000, 0, 0.00, 0.00, 0.95, 2.50, 0.65, 0.00, 0.00, 2, 0.00, 0.00
point.3 = 4.0, -2.855, 5.523, -6.5, 3000, 0, 0.00, 0.00, 0.95, 2.50, 0.65, 0.00, 0.00, 3, 0.00, 0.00
point.4 = 5, -9.5, -5.523, -6.5, 1600, 0, 0.00, 35.0, 0.00, 0.00, 1.00, 1.00, 1.20, 0, 0.00, 0.00
point.5 = 5, -9.5, 5.523, -6.5, 1600, 0, 0.00, 35.0, 0.00, 0.00, 1.00, 1.10, 1.50, 0, 0.00, 0.00
point.6 = 2.0, 3.200, -18.40, -0.652, 1200, 0, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 5, 0.00, 0.00
point.7 = 2.0, 3.200, 18.40, -0.652, 1200, 0, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 6, 0.00, 0.00
point.8 = 2.0, 11.200, 0.00, -4.400, 1200, 0, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 4, 0.00, 0.00


I also changed the Flaps Pitch scalar to eliminate the nose dives on deployment:

pitch_scalar= .1
 
Milton

Just plugged in your contact points...and the plane landed on the water without crashing or flipping over on its nose! You managed to do in just a few minutes what I was not able to do in a handful of hours.

OBIO
 
Thank you Sir. I just tried them against the archive you sent. Seems to work fine.

The aircraft FM in FS9 seems a bit too agile to have all that stuff under it. It would likely be nicer to ease up a bit on the roll agility, and add just a touch more elevator authority.

Yes, if you land near stall with the nose well up, you should have no issues with the landing.

RE: Speed to do this; I assure you that when I was doing the D18S on floats, I spent a few hours on them to get what I wanted so that experience was helpful.

The issue with the original points was the forward points were at the step instead of out front where the fattest, bulk of the float "should be". The rear points should be at or near the step. Rear points should also be a few inches higher than the front (i.e. so the aircraft sits lower in the rear).
 
I did the FD's for the Sky Unlimited Floatfire. I am travelling at the moment and do not have acess to the info on that airplane as it was done. The main reasons that the roll rates will be reduced a little bit is (1) the CG is lowered a bit (2) the moment of roll intertia is increased (3) there is some degree of aerodynamic dampening introduced. Having flown both float and wheel planes the effect is not as pronounced as one might guess as the weigh gain isn't that big since the landing gear has been removed. For a retractable gear aircraft this might take out some hydraulics etc in addition to the gear. The Floatfire was not in my estimation designed to be convertable to a wheel aircraft so would have taken advantage of whatever weight savings and structural simplifications that could be managed.

Cheers: Tom
 
Excellent points Tom. I was thinking having that weight and aerodynamicly messy mass where it is (lower with drag) would affect roll a bit. But I would happily yield to a RW experienced pilot. :wiggle:
 
Milton:

Yes it does change the handling a bit, in a plane like a Spitfire, noted for it's manuverability the change would be noticed in a tactical manuvering situation vrs the identical wheeled plane. However the Japanese float planes such as the Rufe were still viewed as highly manuverable. I would guess offhand perhaps a 10% increase in roll moment?

In aircraft such as the Beech 18, load carrying was essential so the floats were pretty big and heavy. For fighters the load range was much smaller and proportionally the floats smaller and lighter. BTW, your Beech is a nice plane!

Cheers: Tom
 
For those not hip to this plane, it is well worth grabbing. I have two paints nearly done for the plane...one is just a redo of the original desert camo skin that comes with the package, but with crisper panel lines and more sharpness overall (no Mip Mapping on the DXT3 textures). The second is a Dark Green and Medium Sea Gray camo over Trainer Yellow lower surfaces....I based this paint off of images of a model Mk VB Float Plane I found on line. I have no idea if either of these paints are historically correct, but then again, the 3 Mk VBs that were converted to float planes did not stay float planes for long...by the time they made it to the MTO, the course of the war had changed and they were of no use as floaters, so were converted back to conventional geared fighters.

I will upload the skins as soon as I am 100% done with them, have all the FS2004 tweaks in place and any tweaks needed for CFS2 done...one package to cover two sims.

OBIO
 
woohoo, gotta love the spit on floats, if i recall these were operated in greece and never in formations, just 1 or 2 sent to intercept german transport aircraft then bug out... the plan to operate them came to nought though, the island of my birth (Kos) was one such base they had in mind but the idea fell through when the German troops seized the island, if you look at Kos strategically its a sound place, not far off the Turkish coast (supressing my greek feelings towards the T place) more or less central Dodecanese and withing a few hours of the mainland of Greece... plus it's the last place you'd expect to find a spitfire floatplane...
 
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