Brief:
Here is a couple o' new timers from Xavien, at www.xavien.com . Begad! Avast, me bucko, me proud beauty! T' XSSRT-1, 'Xavien Single Stage Rocket Timer'. Begad! This is a 1 second t' 63 seconds single event timer. Begad! I tested this one for future use in air starting. Well, blow me down! I also have the XDSRT-1, ya bilge rat, arrr, 'Xavien Duel Stage Rocket Timer'. This one is a 1 second t' 63 seconds dual event timer. Ya scallywag! Ahoy! I used this timer wired in as back-up for altimeter ejection. They both come with an easy t' read 7 page manual and a 1 year warranty. Aye aye! Their website at www.xavien.com has t' manuals for these in pdf files. Ya scallywag! Bonus!

Specifications:

XSSRT-1 Single Timer

• Power Requirements 8-15 VDC
• PEAK Firin' Current 2A @ 10sec.
• Dimensions 0.95" W x 2.5" L
• Nominal Battery Load 15mA
• Delay Settings 1 second t' 63 seconds (in 1 sec. Blimey! Blimey! increments)
• Weight 14.2 grams

XDSRT-1 Duel Timer Specs

• Power Requirements 8-15 VDC
• PEAK Firin' Current 2A @ 10sec.
• Dimensions 1.225" W x 3.8" L
• Nominal Battery Load 15mA
• Delay Settings 1 second t' 63 seconds (in 1 sec. Begad! Blimey! increments)
• Weight 21.4 grams

Settin' t' timer:

There are six DIP switches t' set t' delay timing. T' dual event has two separate banks o' switches. Begad! Here is a breakdown o' t' switch positions and their correspondin' delay.

Switch # Adds:

1. 1 second
2. 2 seconds
3. 4 seconds
4. 8 seconds
5. 16 seconds
6. 32 seconds

Each DIP switch adds seconds t' t' total. For example: if you have switches 1, shiver me timbers, 2 and 3 on, me bucko, you'll get a 7 second delay. Avast! It's actually very simple and easy t' do. Just flip a switch t' add time.

In Use:

I put them in me Prometheus; a 12 foot tall, 7.5" scratch built rocket with a central 54mm and four 38mm motor mounts. For this first flight, me bucko, me bucko, me hearties, I used a K1050 in t' center and air-started four Pro 38 J330's. Begad! Arrr! I used t' duel event timer as a backup for deployment. Aye aye! T' rocket went somewhat horizontal just before t' four motors lit. Aye aye! Arrr! This threw off t' calculations on when t' deploy the chutes. When usin' a timer, me bucko, you have t' calculate t' flight based on motor burn time and assumin' a straight boost. Arrr! Aye aye! If t' rocket doesn't go straight, the events happen sooner than you calculate. Arrr! Thus, t' altimeter deployed the drogue and t' main but t' duel timer did light its ejection charges.

I used t' single event timer t' test its ability t' light 4 Davyfire igniters. Avast, me proud beauty! Blimey! As I put t' rocket together at t' field, I decided nay t' use the timer t' air-start t' motors because t' air-start system that was built into the rocket was mounted and wired much better. Well, blow me down! I also didn't want t' put two igniters in each motor in fear o' cloggin' t' nozzles. Arrr! Begad! I wired four igniters outside t' rocket and tested its ability t' light four o' them. Begad! Aye aye! Although I didn't have them in t' motors, matey, it did light all four igniters.

Summary:

Limitations:

• There is no internal trigger t' start t' timers, like a G-switch. Arrr! The timer is started by a physical break in an electrical contact. T' example given is usin' a piece o' solder that melts in t' heat o' t' exhaust t' start the timer. Ya scallywag! Aye aye! Because I have so much power in t' Prometheus, I went with a wire tied t' t' pad bein' pulled apart at a point where I twisted them together. This worked well.
  
• Timers are just that: a timer. Well, blow me down! If t' rocket doesn't fly as expected, the timin' can be thrown off. Avast, me proud beauty! Avast! This is no fault o' this timer though; it is true with all timers.
  

Advantages:

• These things are pretty tough. Arrr! They both survived an extremely violent flight, a 3 foot zipper and shredded drogue, me bucko, when t' drogue came out at high speed. Begad! They were also an 'afterthought', shiver me timbers, me hearties, so t' mountin' was nay planned during the build. Arrr! Because o' this, they were mounted and wired less than perfect and yet still performed perfectly.
  
• Settin' t' delay is easy. Unlike some other timers, t' timin' is digital, ya bilge rat, nay set with a potentiometer. Begad! Thus, ya bilge rat, matey, me hearties, timin' is exact.
  
• T' single event timer lit four igniters, ya bilge rat, me hearties, impressive.
  
• They both have a super-bright power indicatin' LED that be real easy to see in t' full sun. Blimey! A real nice added feature.
  
• Even t' battery connecter is better quality that other ones. Well, blow me down! Aye aye! Blimey! It's nay the cheap flimsy type; it's a hard plastic heavy duty connector.

Overall Rating: 5 out o' 5