Building an HPV Fairing

[MetroMPG]

So to clarify... Joint compound is the same as wall mud, correct?

And you abandoned it in favour of bondo for smoothing out the plug because of the bubbles?

EDIT: I can see the attraction of using wall mud - it would be really easy to sand & shape, compared to bondo.

[trebuchet03]

Originally Posted by MetroMPG

So to clarify... Joint compound is the same as wall mud, correct?

And you abandoned it in favour of bondo for smoothing out the plug because of the bubbles?

EDIT: I can see the attraction of using wall mud - it would be really easy to sand & shape, compared to bondo.

Yes, wall mud=joint compound -- I interchange those terms at will (sorry)

We didn't abandon it so much as we used it as a primer/conversion coat. Wall mud cures by drying (which is why it can't get wet). Bondo chemically cures and contains styrene. Because it contains styrene, it will melt polystyrene foam (and won't actually stick). So the mud is used as the initial build up/primer and acts as a compatible layer between the foam and Bondo.

If we wanted to use bondo from the start (no mud), we would need to apply a layer of glass and epoxy resin to serve as a boundary (this is what was done last year).

And yes, wall mud is SO MUCH easier to sand and shape. But it has long cure times. Bondo is much much harder, much smoother when sanded and cures quickly (sets within minutes - or seconds if too much hardener is used )



I think this will be the method used in the future - unless something better comes along

[MetroMPG]

OK, thanks for the clarification. Just thinking ahead to the partial Kammback construction for the Fireflea this summer. I think I'm going to shape a "plug", then glass it to make the part.

[Harpo]

I had the privilege to consult and power a HPA in the early 80's. Unfortunately, the Warped Wing and trailing tail design had big parasite drag problems. I'd trained up to give 'er ~265watts for an hour or two, but any course adjustment made it closer to 300watts. We made our spars with kevlar tape wrapped around aluminum tubing, then ate the aluminum out with acid.

Will this be speed contest or endurance? How many watts will the occupant deliver and for what period of time? I'm a USA Cycling Coach, so I'm very in to the power training.

[trebuchet03]

Originally Posted by Harpo

I had the privilege to consult and power a HPA in the early 80's. Unfortunately, the Warped Wing and trailing tail design had big parasite drag problems. I'd trained up to give 'er ~265watts for an hour or two, but any course adjustment made it closer to 300watts. We made our spars with kevlar tape wrapped around aluminum tubing, then ate the aluminum out with acid.

Awesome!

Originally Posted by Harpo

Will this be speed contest or endurance?

Yes

Points breakdown
Design: 40%
Sprint: 30%
Endurance (relay type race): 30%

Originally Posted by Harpo

How many watts will the occupant deliver and for what period of time? I'm a USA Cycling Coach, so I'm very in to the power training.

We have a minimum of four riders - 1 of which must be female. I've personally been doing 3x5 interval training for the sprint event and then constant wattage training for the endurance.

For the endurance training - I'm trying to work up to 200 watts sustained for 60 minutes. Right now, I'm around 160 on plateau :/ I've got a little more than a month to keep working on it. For the actual endurance event, I'll only be riding for ~30 minutes. What kinda sucks - the recumbent machines that can give wattage readings are in a much more upright position compared to the seat position of the actual vehicle - but, my own 'bent is a bit closer to the actual seat position



Oh, and original post updated

[Harpo]

How long is the sprint in minutes?

I have some training recommendations for the endurance/tempo 30 minute effort. You can make some progress in four weeks. Assuming 160watts is your 60 minute power.

Tempo work is good, but to really get the metabolic changes, you need to be developing closer to the watts you want to meet. The bread and butter training for 30 minute efforts are 8-20 min., sustained efforts.

Week One
Tues - 3 reps x 8 minutes with 2 minute recovery (180 watts)
**Minutes 6-8 should require concentration to maintain rpm, but you should not be anaerobic and gasping for air**
Wed - 2 reps x 8 minutes with 1:30 minute recovery (180 watts)
Thur - Spin 45-60 min. in Zone 1 HR (<=120 watts)
Fri - 3 reps x 8 minutes with 2 minute recovery (180 watts)
Sat - OFF or Spin 20-30 min. in Zone 1 HR (<=120 watts)
Sun - 60-90 minute tempo (avg 150 watts)
Mon - OFF or Spin 20-30 min. in Zone 1 HR (<=120 watts)

We can possibly work up to 12's at 190 watts, but 200 watts will be a stretch with roughly 12-14 workouts.

[MetroMPG]

Originally Posted by Frank Lee

When I built a foam/glass body for a SAE super-high mileage car...

I didn't know about this. Post up a thread, Frank!

I don't suppose you have any pics?

[MetroMPG]

Originally Posted by trebuchet03

the recumbent machines that can give wattage readings are in a much more upright position compared to the seat position of the actual vehicle

Are there design restrictions on seat angle/height?

[trebuchet03]

Two day update! Today was a sad update though

[MetroMPG]

Well, happy belated.

Interesting method of getting the foam out, for sure!