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  • Users: Rat5
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  1. Rat5

    Riveted joints / structures

    Hi, i have a few questions about the riveted joints that hold a aircraft together : -Does the rivet retain axial preload from being bucked ? if yes how to calculate the value ? -Does a riveted joint provide strength from the friction between the 2 sheets jointed together and normal load on...
  2. Rat5

    Riveted chassis and FEA

    Hi, How would one go about modeling riveted joints of a riveted aluminium sheet monocoque on Solidwork FEA ( or another ) ?? should i use bolts, or simplify by juat surface contact and clamping force ? If yes how do i calculate clamping fprce of a rivet ? Thank you
  3. Rat5

    Fabricated crankshaft, racimg motor, viable option ?

    Is a fabricated crankshaft a viable option for a turbo racing engine ? (4 cylinder / 2 litre / approx 800Nm ) By :fabricated" i had in mind : Bored plates that act as throw/counterweight and the pins and mains would be pieces of round stock, all press fitted together and welded, by tig...
  4. Rat5

    Compound turbochatging / wastegates

    Hello, I came across this video of THailand drag trucks. They use compound turbo systems. However, it seems that they dont reintroduce HP wastegates outlet before LP stage. (wastegate on collector, before small HP turbo dumps to open air) Is there a strategic reason behind this ? To me...
  5. Rat5

    1980s F1 Fuel, Toluene Diesel blend

    Hello, I know they used Toluene and like 30% Diesel, Why diesel ? Some say it is to slow down combustion butbi dont believe it is that, and it would not be beneficial to do this. I think it was done to lubricate the mechanical injection system.
  6. Rat5

    Spring preload and load...

    Hello, can someone explain me something i struggle a bit with ? Lets assume a spring / mass system (like the corner of a car ) If i have a linear spring, with 10kg/mm and i put 300kg of preload, the spring will be compressed 30mm. Now lets assume the corner of the car is 400kg, when you...
  7. Rat5

    Cooling system design, mass flow rate ?

    Hello, Anyone have a good method or book/sae paper suggestion on how to calculate required coolant mass flow rate and radiator area ?
  8. Rat5

    Effect of rebound dampening on jumping vehicle ?

    Hello, What effect does rebound damping have on a vehicule taking a jump ? (MotoX or trophy truck for example ) In my opinion, little rebound damping (faster rebound) causes the vehicle rear to ride high, because the action of the wheel going down will equally push the vehicle up, correct ...
  9. Rat5

    Turbo inline 4, exhaust design sound

    I always wonder why, turbo inline 4 can sound so different , Like these for example have a "smooth sound" if i can say https://youtu.be/wWr1uGbhAP8 While some have that particuliar aggressive sound that reminds of a subaru https://youtu.be/tMjALs931aE https://youtu.be/jjeBJd6ZynA I would...
  10. Rat5

    Engine testing, boosted air supply control

    Hello I was watching this F1 documentary where they show an engine on the dyno and they use an industrial compressor to provide boosted air What kind of control strategy would be used here for pressure control ? Starts at about 12 mins in https://youtu.be/xbB1qwhKaaE
  11. Rat5

    FWD Vehicule caster

    Hello, Why does generally FWD and AWD vehicles have less caster angle than RWD vehicles ? Is this to lower the self centering effect of the driven wheels ? Thanks
  12. Rat5

    Differential crown gear

    Hello, Why does in a differential, im common systems when going forward, the pinion gear's concave face attacks the convex face of the crown gear ? I struggle to understand the advantage here ? Why not the other way around ? Thanks
  13. Rat5

    Helper spring ?

    If the helper springs purpose is to keep the main one aligned during full extension, why not just use longer spring ?
  14. Rat5

    F1 engine, deck ridges ?

    What are those small deck ridges ? ( bmw f1 engine 1500cc 1200hp)
  15. Rat5

    Pisto/bore clearance at operating conditions.

    Say you have an engine with a aluminum piston in an iron bore, and about 5/100ths of clearance 0.05mm static. What is the average clearance when the engine is running ? I heard somewhere that the piston is almost a press fit and the oil film keeps it fron seizing ? Looking for actual...
  16. Rat5

    Load vs Timing advance

    Hello, While i understand that you need more advance as the rpm climbs, i struggle to understand why timing decreases as load increases ? There is more mass to burn why would it burn faster ? Flames do travel faster in hot environement ( more load, more mixture prensent, more end of comp...
  17. Rat5

    Piston area ?

    Consider 2 engines with a 90mm bore. One has a flat piston The 2nd has a spherical piston Will the one with the spherical piston make more torque because there is more piston area ? Or are you supposed to use projected ( so bore) area for this calculation ?
  18. Rat5

    80+ PSI boost, single stage, how ?

    Hello, I seen many engines with single turbos with around 60 to 80 pounds of boost ( 4 or 5 bar) they did so in f1 in the 80's How is it possible with a single turbo ? Its way off the compressor map ! https://youtu.be/_yeJB2-mELM
  19. Rat5

    Tuned intake length

    Hello, here's a formula that was provided by someone on the web. We keep arguing. I think it is complete nonsense. What do you think ? L=10.Cs/n[1/(K/(1-(1.62 u/Cs S/Ac)^2))+((1-K)/(1-(1.62 u/Cs S/Ac 2/(Amt/Ac+1))^2))] L: runner length S= piston area u= average piston speed m/s. Ac=...
  20. Rat5

    Crankshaft counterweight shape ?

    Hello, Why do some counterweight have "ears" whereas some are very narrow ? Are the ones with ears for balancing piston movement over a greater "sweep" of crank ? See pics for referemce. Thanks Small sector Big sector (ears)...

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