incubator heat bulbs blinking new build

[CMH70]

Howdy everyone. I used this idea to build an incubator.

https://www.backyardchickens.com/a/homemade-incubator

differences being... taller for double stack 2 turners, 2 -40watt bulbs and 3255 gqf thermostat, air pushed by 2 small 2 1/2" fans. bulbs and fans in a rear chamber to suck air from under eggs and push warm air over top. thermostat in turner chamber with the eggs.
now... holds temp rock steady at 99.5 but bulbs cycle off and on no less than once per second. via this normal and will the bulbs last like this?
note... the bulbs cycle normal without the fans and temp varies 2-3 tenths but I want the fans.
turners 12x18x18 w/heat box 12x8x18 on back. 3x3 hole air flow top and bottom inside.

 

[lazy gardener]

try repositioning your fans. sounds like they are drawing too much air across the bulbs/thermostat, so it's cycling too fast. Where is your thermostat in relation to your heat source, and how close are the fans? Check out Rush Lane Poultry. He has some excellent videos on bator builds.

 

[CMH70]

thermostat is on other side of 3/4 plywood from bulbs but close to air flow. we may try relocate it.
yes Rush Lane Poultry's videos are good and on my fav list.

I'll post a video as soon as I figure how to from my phone. away from home for a few days

edited to add video links

Here is a link to short video showing how fast the bulbs blink.

http://curtism70.fatcow.com/Blinking.3gp
and
http://curtism70.fatcow.com/Blinking1.MOV

got word it held rock steady all night last night