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whoah, go away for 10 days and have 48 new message #1268
07/31/01 05:14 AM
07/31/01 05:14 AM

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whoah, go away for 10 days and be faced by 48 new messages that need your attention !
<br>
<br>I see that I'm a little behind.
<br>
<br>I see that both John P and Steward are itching to design a F16 HP (!!!) from scratch :
<br>
<br>If I remember correctly another F16HP collegue said something along the same lines.
<br>
<br>If Wouter gets Ventillo on board too than we'll have four teams working on four new and optimized to F16HP designs ! Can someone please pinch me for I must be hallucinating.
<br>
<br>'My views :
<br>
<br>Okay on 9 mtr. max mast
<br>Okay on width 2,5 mtr. if wings are still allowed. So 2.5 is max width base platform.
<br>
<br>Okay on genaker area 17,5 sq.mtr. (but I'm biased for I'll be sailing solo alot)
<br>Okay on luff length 7,550 mtr. and taking hoist height in stead of actuall draw height.
<br>
<br>Not okay on min weight up to 110 kgs, I vote for min. 100 kg's
<br>Not okay on max length 5,05 or so, keep 5.0 mtr. and make an exception for the 5,03 mtr. long Stealth. Newly designed stealth NOT included in this exception.
<br>
<br>ISAF for handicap calculation sounds better than Texel. ISAF has a better International ring to it and will be accepted more easily by non Dutch sailors. And isn't France (a major player) using ISAF officially ?
<br>
<br>On regulating boards, can't we leave this open and correct any rating differences using the jib area ?
<br>
<br>Now on F18 equality. A very nice concept and must be kept into the framework but it looks like the F16HP can go alot faster. Isn't it a good idea to open up a way to grow to a truelly maximized F16HP.
<br>
<br>I had a discussion with Wouter just last sunday about this and the idea was coined to regulate F18 equality in the F16HP framework and use this setup for solo sailing and for the first F16HP races like maybe Texel 2002/2003 or a Caribian regatta. Later when the class has started we de-regulate genaker size and abandon the F18 equality for pure F16HP 2-up races (solo will still use the F18 equality setup). This will mean that the F16HP 2-up will fly bigger genakers of probably around 21 sq. mtr. maybe even with longer poles and use the large 4 to 4,25 sq. mtr. jibs.
<br>
<br>This will make the F16HP about 3 % faster (according to wouter and don't ask me how he calculates these things) and put the F16HP somewhere halveway between the iF20 and F18 performance. He also said something about beating the iF20 in light air but I can't remember wether that was on handicap or allout.
<br>
<br>I probably said more than I should have, sorry Wouter, but there is something irrisistable about pushing the F16HP passed the F18 and onto the iF20.
<br>
<br>If I understood it correctly, the upgrade from "equal to F18"to F16HP allout would involve a new genaker, replacing (or adding) the hoist point, buying a bigger jib and bending two aluminium tubes into wings. I quote Wouter: "conversion cost about NFL 2500,- (US$1000,-) or less." The smaller genaker (and smaller jib) can be kept for solo sailing or F18 handicap racing or use to implement a F18 style of equalizing crewl weight differences.
<br>
<br>It sounded good on the beach. And sorry for steeling your scoop Wouter.
<br>
<br>Anonimous4
<br><br><br>

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Re: whoah, .... , Indeed the last time I tell you. #1269
08/01/01 07:40 PM
08/01/01 07:40 PM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
Carpal Tunnel
Wouter  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 9,582
North-West Europe
Whoah, .... , Indeed, ... the last time I tell you anything <=) (joke)
<br>
<br>Anyways the beating F20 part was allout in light air due to small wetted surface.
<br>
<br>Go to your projectgroup webpage and click the new links for more info on this.
<br>
<br>Wouter
<br><br><br>

Attached Files
1279- (142 downloads)

Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
More on width #1270
08/01/01 09:16 PM
08/01/01 09:16 PM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
Carpal Tunnel
Wouter  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 9,582
North-West Europe
First the width of the craft.
<br>
<br>Take a look at page
<br>
<br>http://www.geocities.com/F16HTclass/F16HT_to_F18_equality.html
<br>
<br>It has been severly updated, you will be familiar with large parts of the text but there are some big parts newly added.
<br>
<br>Some due to my friend here blowing the wissle. Okay width :
<br>Another lucky guess gentlemen for it appears that 2,5 mtr. as a maximum width coincides perfectly with a 83 % thrust in the stronger winds. Calculation goes as follows :
<br>
<br>ratio righting moment doubled trapezed F16HP/F18= (150 *3,5 + 100*1,25) / (150 *3,6 + 180 *1,3) = 650 / 774 = 0,8398 % = 84 %. The sailarea ratio F16HP/F18 = also 84 % and both masts are equally high. So both crews will be double trapped in the same windstrength and depower at the same time thus the max thrust ratio will be fixed 84 % too ! So if the high speed drag is 84 % too than an F16HP at 2,5 mtr. width will be perfectly equal to the F18's. When the platform isn't then wings providing extra width can raise the thrust ratio in these conditions. Example : Width goes to 2,7 (0,2 mtr, wings on both sides)
<br>
<br>150 * (2,7+1) + 100 * 1,35 = 690 kgm
<br>
<br>then
<br>
<br>690 / 650 = 1.0615 = 106 % more heeling resistance this leads to the F16HP rig being able to produce 6 % more thrust than it would at 650 kgm anti-heeling moment. And this is produced at 103 % the windstrength at which a F18 starts to depower. Which is nearly nothing, hardly noticable, but the 6 % increase in Thrust isn't so small !! And best thing about this setup is that it leaves light and medium air characteristics unaffeacted. Make the platform wider only boost heavy air performance and nothing else.
<br>
<br>So we have :
<br>
<br>1 Genaker to finetune downwind performance
<br>2 Jib to fine tune upwind performance
<br>3 Width to finetune heavy air upwind performance
<br>4 Rather long upwind beats and short downwind tracks making any heavy air downwind performance difference to have a rather small impact on the overall result. Less impact time thus speed differences on this course are relatively unimportant ; analogue to cat-skiff paradox.
<br>
<br>And we already had equality in the light air due to the lightweight and 83 % wetted surface area. Seems to me that we've got all the finetune mechanismes we want to make the F16HP equal to the F18 class. And max width 2.5 mtr. is a very good starting point.
<br>
<br>
<br>Wouter
<br>
<br>
<br><br><br>

Attached Files
1286- (141 downloads)

Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands

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