SEN 1778

Table of Contents - SEN 1778

  1. F1B LDA
  2. USA 2015 team selection
  3. F1B for sale
  4. USA Nats scores

On Trimming an LDA F1B Model

 

LDA-B models tend to fly straight as on rails until they lose steam and wobble into their course. About a month ago at Wawayanda, in a strong wind, my LDA-B model actually did a large loop, fortunately missing the ground to clock a minute plus result.  Carrol Allen suggested taking out some wing wiggler to help the model rotate during the burst.

 

All my B models have a Vivchar double wing wiggler, but I only wiggle the left wing during the climb. Although I’ve tried to use the right wing wiggler (which reduces the wing twist and comes out at 7-10 seconds), it did not seem to make a difference. So, following Carrol’s remark, I hooked up the right wing wiggler.

 

The results were spectacular (after some trimming). The model climbs and rolls nicely into cruise, without a VIT bump or hesitation. The launch has to be steep, as the model tends to fly straight initially.  Of course one use a single wing (left) wiggler, but it will have to be a compromise between the burst and cruise. In a Vivchar model, the left tailing edge is typically raised by .060”, the right by .020”.

 

The conventional wisdom is that a LDA-B model should fly with a fix pitch propeller. Instead, I’m using a 13 degree variable pitch front end and the model is perfectly happy. The motor runs seem to be short and one has to increase the blade’s cruise pitch a bit.  A number of observers claim that the model whistles in burst but they probably have better hearing.

 

No, I have not attached an altimeter to check the altitude. LDA-B models don’t glide as well as models with conventional wings and have a nasty tendency to start stalling after a while in laminar conditions. Fliers have tried various fixes and I use single layer tape invigorators at 50% and 65% of the wing.

 

Aram

 

Editor's comment:

 

Aram - I also have found that a VP hub is better than a FP and used an altimeter to test this. Incidently Vivchar is about to release a VP hub that will help with LDA airplanes as it has a low high low pitch cam.  A umber of people have already modified Vivchar VP hubs to do this.   I have found that using Vivchar's "LDA-like" wing I can get at least 15 meters more altitude than with his similar conventional airplane.  This is a Eppler airfoil with a big Phillips entry but more flap than other LDAs so it probably has more drag than the Eggleston sections in common use. This airfoil seems to handle turbulence better than some of the other sections.  Maybe an indication the amount of "LD" in an LDA F1B is the length of the VIT .  With a conventional airfoil I have about 4 seconds while with this LDA I have about 5.  I have watched Michael Seifert testing one of Stepan's models with a Eggleston LDA and he had about 7 seconds of VIT



USA Team Selection for 2015 Time Accumulation

 

Everyone seems to be occupied with the upcoming world championship in France, which is fine. But, for some reason, very few contests this year have been posted in a round-by-round format on SEN (as maxes need to be normalized) or sent to me.

 

So please nudge your CDs to do their reporting to Jim Parker (American Cup) and me. The time accumulation sheets results will be posted on the NFFS site www.freeflight.org

 

Happy flying (that counts).

Aram

 

F1B For Sale

 


 

I would like to sell a brand new Vivchar F1B that has been flown only once by Mike Mulligan in order to prove that it is perfectly trimmed
and it flew very well.
  I am asking only $850 for it and I shall pay the shipping as well.

  My name is Phedon Tsiknopoulos and my email address is:
  This email address is being protected from spambots. You need JavaScript enabled to view it.



Nats Results

F1A Nats
1 FOJAMA DANIERONTARIO, CANADA1288
2 OCHARLES S MARKOSDEERFIELD, IL1084
3 OLEE R HINESCOSTA MESA, CA1070
4 OGENE C ULMFAIRFAX, VA1059
5 OROBERT SIFLEETGLEN ROCK, PA1053
6 OTIMOTHY R BARRONNORTH HAVEN, CT1041
7 OJEFF FEDORGRANDVIEW, TX911
8 OANDREW R BARRONNORTH HAVEN, CT853
9 OCHARLES R JONESAVON LAKE, OH400
10 OMIKE FEDORARLINGTON, TX307
11 FORICHARD W BERTRANDGUATEMALA CITY, GUATEMALA183
12 OJOHN E LORBIECKIHUBERTUS, WI69

F1A Jnr

1 JALEX STALICKALTADENA, CA1102
2 JGINA G BARRONNORTH HAVEN, CT899
3 JCADE FEDORGRANDVIEW, TX549
4 JCOLBY M FEDORGRANDVIEW, TX130

F1B

Tom Vaccaro
Charlie Jones
Blake Jensen
Tom Ieorger





F1C
Faust Parker
Gil Morris
Bucky Servaites




F1p oPEN AND sNR

1 OROBERT M HANFORDBROKEN ARROW, OK596






F1P Jnr

1 JCADE FEDORGRANDVIEW, TX572
2 JCOLBY M FEDORGRANDVIEW, TX444



F1Q

1 OJULIE E PARKERHOUSTON, TX921
2 OMARK FREELANDKEEGO HARBOR, MI869
3 OPAUL S MASTERMANCHESTERTON, IN803
4 OJAMES T JENNINGS JRGALLATIN, TN677
5 ODAVID W LACEYALEXANDRIA, VA619
6 OARAM C SCHLOSBERGOAKLAND GARDENS, NY576
7 OJACK MURPHYSALT LAKE CITY, UT498
8 OANDREW D TOMASCHNORTHVILLE, MI113





...........................
Roger Morrell