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  • Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.

    Post 16 Update

    Post 17 Warning

Elco 80 Foot PT/MTB boat dynamics overhaul up

warchild

warchild

Charter Member
These dynamics should be able to be used with any rendition of the Elco 80' PT Boat. Utilizing the Packard 1350 hp V-12 piston engine found in the 103 class PT boat of 1944 - 1945 these dynamics allow for smooth acceleration through the entire speed range with none of the typical bobbing caused by fsx thinking its a pontoon on an airplane. Maneuvering is not as quick as it has been on other variants of similar models made by me but that is to reduce the amount of capsizing and roll overs in high speed turns.

to install this, you will need to copy the [Flitsim] and [camera] sections from your existing Aircraft.cfg files and paste them into this new aircraft.cfg file. I did this to eliminate any possibility of copyright infringement that may have existed and i do apologize for that inconvenience. Please make no mistake. this is an entirely new model, and should work well with any 80 foot version of the Elco PT/MTB vessel available..

the download can be found at the bottom off the page at http://www.sim-outhouse.com/sohforums/local_links.php?catid=4&sort=h&page=5&pp=20 , or you can search on Elco-80_PT-MTB_FDE-RC1.zip in the SOH library
Enjoy.
Pam

PS. I do not make a claim that these dynamics are accurate. they are a work in progress still. The Class 103 MTB was ( because of the weight of the armament ) unable to accelerate past 41 knots, but due to the limitations of FSX i purposely made the boat go to over 50 knots to overcome the constant bobbing that fsx does with floats. I'm still working on finding ways around that so that i can bring you an accurate flight model in the future..
Thanks.
 
Just finished the download Pam, I am off to give it a try. My latest effort has been at Apra Harbor, Guam and this is a great place to test her out. Thanks for doing this. This is a great looking model and deserves the attention.
 
I agree. The Deltasim model is a great looking boat.. I do apologize that i had to create a generic and non-specific flight model for Elco-80s in general, but realities being what they are I am no longer able to work specifically on the Deltasim product.
However, should things work out, there may be something on the horizon. Stay tuned :)..
Pam
 
Pam, this version works extremely well. All is perfect with the way the boat glides over the water. The only thing noticed is with the rudder set to middle the boat pulls slightly to the left. I first thought this was because my auto rudder setting are set to off. Even with auto rudder set to on it still pulls slightly to the left. Easily controlled with slight rudder right.

If this is an easy fix that would be great, if not it is totally acceptable. Thanks for all your hard work.

ApraHarborGuam2_zps3fa73274.jpg
 
Err wait.. Its pulling left??
ok.. in the [weights and balances section of the config file theres an entry that says

empty_weight_CG_position= 0.00,0.05,-3.35 //-27.0,0.0,3.35

Your going to have to play a bit, but its that second entry ( 0.05 ) that needs to be changed. you can try centering it ( 0.00 ) but that should make it pull more to the left.. Moving it out further ( 0.15 ) should pull it back to the right..
When i was making adjustments to the contacts for the effects files, i noticed that the ship was rendered off center, but i didnt know it could have an effect on the way the ship handles.. It may need to be looked at more closely.
Pam
 
Yeahhh, that setting helps a tiny bit..
Whats happening is that as the angle of attack changes and the bow comes up out of the water, gyroscopic precession cuts in and starts doing its thing. its like driving a motor cycle then. as you lean in one direction, the gyroscopic precession tends to pull you in that direction. only, in this case its pulling strong enough in the opposite direction to overcome the offset of the Cg.. I'm going to need to work on that and issue an update as each time the bow of the boat bob's up, you lose approx. one quarter to one half a degree to the left..
Also, dont trust the auto pilot. i havent been able to get that thing to work at all..
I'll keep working on this though. i promise..
Pam
 
I found it helped slightly as you mentioned, but there are other forces working here. I changed that number to 45 from 05 to see what happens and the vessel leans over to the right. I have changed back to 15 as this seems to be best right now. Awaiting any new changes you find. The dynamics as of now, are the best yet. Thanks
 
Ok Tom.. copy the two sections pasted below ( [weights and balances] and [flight tuning] ) and paste them into your aircraft.cfg file replacing the existing sections. this should help immensely..
Pam

[WEIGHT_AND_BALANCE]
max_gross_weight =72000
empty_weight=61000
reference_datum_position=0,0,0
empty_weight_CG_position= -3.00,0.00,-3.35
max_number_of_stations = 5

station_load.0 = 200, -0.6, -2.4, 3.35

empty_weight_pitch_MOI = 9646.46832
empty_weight_roll_MOI = 36600.48976
empty_weight_yaw_MOI = 609788.9168
empty_weight_coupled_MOI = 386.070

CG_forward_limit= 0.0
CG_aft_limit= 0.0


[flight_tuning]
cruise_lift_scalar=3.0
parasite_drag_scalar=4.75
induced_drag_scalar=2.0
elevator_effectiveness=1.00
aileron_effectiveness=1.0
rudder_effectiveness=1.0
pitch_stability=0.63
roll_stability=1.000
yaw_stability=1.000
elevator_trim_effectiveness=1.000
aileron_trim_effectiveness=1.000
rudder_trim_effectiveness=1.000
p_factor_on_yaw = 0.00
torque_on_roll = 1.83
gyro_precession_on_yaw =0.01
gyro_precession_on_pitch = 0.917
gyro_precession_on_roll =-3.00000
hi_alpha_on_roll =-2.00000
hi_alpha_on_yaw =-5.00000
 
Pam, the new files work perfect for me. The boat is balanced and as Tom already said floats over the water. Turning feels very natural now :salute:.

I haven't noticed any preference to pull to the left (or right).

Thanks,
Huub
 
fantastic Huub. Thank you.. Guess its time to hook up the X-65 ( shudder ) and let it give me more exact responses.
 
What i could also do is reactivate the trim. PT boats dont have trim as they're pretty straight forward machines (unlike deep sea competition boats with trim flaps and other devices ), but, it would allow each user to have a way of adjusting the directional stability regardless of the files/machine/whatever may be happening..
 
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