First Electric van boat tail

[freebeard]

Coventry University documented the boxed cavity, apparently better than a flat bulkhead.



The guy's name will come to me later.

[JohnForde]

Originally Posted by freebeard

Coventry University documented the boxed cavity, apparently better than a flat bulkhead.



The guy's name will come to me later.

Thanks for the tip Freebeard. I think the question before me is not how to do the most efficient tail but rather the most efficient way to get some measurable performance from my current tail. If leaking is suspected a second seal at the rear might be very practical.

[Piwoslaw]

Another idea to cross check the effects of the tail you already have is not to keep an eye on momentary energy consumption, but to do a coastdown test, where you see how far you car will coast in neutral from a set point and speed.
Maybe then you'll see an improvement with the tail, compared to coasting without?

[aerohead]

If the 'up-stream' transverse contamination were to remain, the pressure recovery would remain compromised, leaving the new rear 'base' at the lower-than-achievable pressure. No gain.
Adding compressed air to a 'blown' tire isn't a proper analogy, but the result is similar.

[JohnForde]

Originally Posted by aerohead

If the 'up-stream' transverse contamination were to remain, the pressure recovery would remain compromised, leaving the new rear 'base' at the lower-than-achievable pressure. No gain.
Adding compressed air to a 'blown' tire isn't a proper analogy, but the result is similar.

I can't figure out where the upstream transverse contamination is coming from.
Both the top & bottom seem well sealed. Here are 2 photos.

[JohnForde]

Black HDPE in 1st pic has been replaced by tightly fit white coroplast.

Can't figure out why I get no improvement.

Is it leaking?
Is it the cuff?
Thoughts anyone?

More pics on request.

Thanks
John Forde

[freebeard]

Next week I will begin pressure testing. Thanks to Vanm455 for sending me pucks.

Hopefully, something will come of this.

[ennored]

Pressure data will be great, but I think tuft testing would tell you what's going on near the transition to the tail. You'd think the long wheel base Brightdrop would be long enough to have nice flow near the back along the sides, but maybe not? Tufts ought to tell you. You did mention doing it this week, I wouldn't hold that up getting pressure transducers set up.

[CigaR007]

At this point, without any flow data, be it visual cues or pressure readings, it is like shooting in the dark.

[JohnForde]

Test tomorrow if I can find a chaser.