PedalTheOcean.com



THIS BLOG HAS MOVED
adventuresofgreg.com





New confusing speed data


It was a perfect weather day today so I got the record boat out to Elbow Valley community lake and ran some test with the new short flexible shaft and free hub:
  • #1 flex shaft, small rudder, freehub, 150 watts = 11.9 kph
  • #2 REPEAT of #1 = 11.8 kph
  • #3 REPEAT of #1 = 11.8 kph
  • #4 100 watts = 10.3 kph
  • #5 200 watts = 13.2 kph
All of these speeds are almost exactly as per Ricks predicted speeds so this is very good news.



The spring steel shaft felt good - about the same as the stainless shaft I had on before. My speeds were about .1 kph faster with the smaller shaft diameter and length.

The other good news was the freehub that I coupled to the shaft worked very well. It allowed me to coast without pedaling whereas before, when I stopped moving the pedals, the prop would stop also and cause drag. However, it did nothing to change the feel of the normal pedal action and I found that I missed not being able to pedal backward to clear weeds from the prop or to go in reverse. I don' think that the weight or complexity of the freehub is worth it for the record boat. I don't plan on coasting at all anyhow. Here is a video of the freeprop spinning:

video

I've been waiting for decent weather, so I took the opportunity and packed the boat up and went to Glenmore reservoir to test some longer, straighter runs with some disappointing results:
  • #1 1 km out and back = 11.1 kph
  • #2 1.3 km out and back = 11.1 kph
  • #3 1.3 km big loop = 10.9 kph
  • #4 .8 km loop, NO RUDDER = 11.6 kph (10 kph wind)
  • #5 .8 km loop, BIG RUDDER = 11.1 kph (10 kph wind)
The reservoir is VERY dirty because of the high water flow and flooding this year. At one point near the canoe club I went through a large patch of branches, logs, weeds, etc. I had to pull weeds off the prop and prop strut and there may have been some weeds on the rudder. I didn't count this run because of this. The runs that I did count were in an area that didn't have any visible weeds and there were not weeds on the prop or rudder before or after runs.

So why were my long runs at Glenmore so much slower than at Elbow?

Is it possible that at the small Elbow valley lake I am taking advantage of a counter clockwise flow in the lake? I doubt it because I don't really ever notice any kind of drift when sitting still.

My rudderless run at Glenmore was very close to the speed of the rudderless run at Elbow if I subtract .2 kph for 10 kph winds. Also so was the small loop big rudder run. The only difference was that the initial runs were either straight or a large loop. This makes me think that my slower speeds at Glenmore are due to the straight line route or very large loops that I did. Perhaps the boat is more efficient if it is making a small, constant left hand turn.

To confirm this, I need to get back out to Glenmore (or some other large lake) and repeat tests with various loop diameters and directions. Here is an updated speed table:

date lake power watts wind kph waves rudder prop loop size km loop dir hull floats other SPEED kph
06/05/08 elbow 150 5 ripples big thin .5 counter taped norm
11.1
06/09/08 elbow 150 calm flat big thin .5 counter painted norm
11.2
06/09/08 elbow 150 calm flat small thin .5 counter painted norm
11.7
06/09/08 elbow 150 calm flat small thick .5 counter painted norm
11.7
06/09/08 elbow 150 calm flat small thin .5 counter painted norm prop strut pulled into hull with cord 11.6
06/09/08 elbow 150 calm flat none thin .5 counter painted norm
11.8
06/09/08 elbow 150 calm flat small thin .5 clock painted norm
11.1
06/09/08 elbow 150 10 ripply small thin .5 counter painted norm
11.5
06/12/08 elbow 150 20 waves big thin .5 counter painted norm
11.0
06/09/08 elbow 150 20 waves big thick .5 counter painted norm
10.9
06/09/08 elbow 150 20 waves small thick .5 counter painted norm
11.3
06/09/08 elbow 150 20 waves small thin .5 counter painted skimmers rods 10
06/09/08 elbow 150 20 waves small thin .5 counter painted skimmers no rods 10.2
06/16/08
elbow
150
calm
flat
small
thin
.5
counter
painted
norm
flex shaft & freehub
11.9
06/16/08elbow150calmflatsmallthin.5counterpaintednormflex shaft & freehub11.8
06/16/08elbow150calmflatsmallthin.5counterpaintednormflex shaft & freehub11.8
06/16/08elbow100
calm
flat
small
thin
.5
counter
painted
norm
flex shaft & freehub10.3
06/16/08elbow200calmflatsmallthin.5counterpaintednormflex shaft & freehub13.2
06/16/08Glenmore
150
calmflatsmallthin2
out&back
painted
norm
flex shaft & freehub11.1
06/16/08Glenmore150calmflatsmallthin2.6
out&back
paintednormflex shaft & freehub11.1
06/16/08Glenmore150calmflatsmallthin1.35
counter
paintednormflex shaft & freehub10.9
06/16/08Glenmore15010
ripply
none
thin
.84
counter
painted
norm
flex shaft & freehub11.6
06/16/08Glenmore15010ripplybig
thin
.8
counter
painted
norm
flex shaft & freehub11.1
06/17/08Ghost
150
5
ripply
small
thin
.8
out&back
painted
norm
flex shaft & freehub11.6/11.2 = 11.4
06/17/08Ghost1505ripplysmallthin.52counterpaintednormflex shaft & freehub11.5
06/17/08Ghost1505ripplysmallthin.56clockpaintednormflex shaft & freehub11.6
06/17/08Ghost15010ripplysmallthick1out&backpaintednormflex shaft & freehub11.7/11.2 = 11.4
06/17/08Ghost15010ripplysmallthick.7out&backpaintednormflex shaft & freehub. NO PROP STRUT
11.8/11.2 = 11.5
06/28/08U Kanan
15010waves, ripples,
some calm
smallthin7.19out&backpaintednormflex shaft11
06/28/08U Kanan1505ripples
smallthin1.19clock

flex shaft11.5
06/28/08U Kanan1505ripplessmallthin1.13counter

flex shaft11.5
06/28/08U Kanan15010waves, ripples
smallthin10.3giant loop of lake - counter


flex shaft11
06/28/08U Kanan12010waves, ripples,
smallthin10.1giant loop of lake - clock

flex shaft10.1
06/28/08U Kanan1205ripples

smallthin1clock

flex shaft10.5
06/28/08U Kanan1005ripplessmallthin1clock

flex shaft9.6
Observations
1. Every 5 kph of wind equates to .1 kph decrease in speed
2. Big rudder is .6 kph slower than small rudder. Small rudder is .1 kph slower than no rudder
3. Right hand turns dramatically slow the boat down.
4. Paint vs packing tape was worth a speed increase of .1 kph
5. Elliminating the prop strut is worth an additional .1 kph in speed.
6. Counter clockwise loops at Elbow Valley lake are worth an additional .2 to .3 kph average speed due to current (??? need to verify)
7. remove the seals and backing off the lock-nuts on the gear box are worth an additional .1 kph average speed.
8. The narrowed 1/4" spring steel shaft compared to the 3/8" stainless shaft is worth .1 kph speed increase





Labels: ,

5 Responses to “New confusing speed data”

  1. # Blogger fhe

    it is possible that your boat is tuned for slow turns. Kinda like an Indy car. Forcing it to go straight must take some force (and drag) and that could be responsible for slower speeds.  

  2. # Anonymous Anonymous

    Greg, the offset propellor and torque wants to turn the boat to port, all you have to do is work out the best speed radius the boat travels at and use that for the record attempt. Russell  

  3. # Blogger Adventures of Greg

    offset thrust turning to port: We have calculated that the amount of power from rudder to correct the offset thrust is VERY minimal. There is something additional which is causing the lower speeds going straight.

    It is true that I could just find the ideal radius and use that for the record attempt course, but it would be small - probably about 1/2 km circumference. YIKES! I can't imagine going around that for 24 hours. It would be like the 1/4 mile race track in Eureka during the 24 hour HPV record.

    gk  

  4. # Anonymous -S

    Hey greg, depending on where you were running, there's a noticable current in the reservoir right now due to the water being so low. The channel (or river if you will) is much more pronounced and depending on where your speed runs were, this could have affected you.  

  5. # Blogger Alex

    Greg, out of interest is it at all possible for you to sling the prop over the other side and see what happens? Or is it one side only?  

Post a Comment


Subscribe to email updates:

Name:
Email :


About Greg video:



    follow me on Twitter





      Adventures of Greg Home
      PedalTheOcean.com
      Motivational Speaker





      featured slide show:



      Archives (newest first)





        Web This Blog



    © 2006 PedalTheOcean.com | PedalTheOcean BLOG by Greg Kolodziejzyk.
    motivational speaker
    No part of the content or the blog may be reproduced without prior written permission.